For the diode you could go to radio shack and pick up a silicone diode. A 2 amp or higher should be fine at around 1KV piv or higher. If you feel capable and replace it yourself be sure to get the polarity right. White stripe on diode to pin 5. If you put it in the wrong way you will create a short circuit to ground.

If the CCRM is messed up bad it might be easier to just get a new CCRM. Not just yet though. Perform a few more tests to confirm and let ROD go over my test analysis.

There also seems to be external problems on the wiring to pin 24.
Not sure about the diagram but what the hell is a "high speed electro drive fan"?

All depends on the test. No offense but some of your earlier tests were a little foggy. The one you did last night seemed to be very good though. Rerun all failed tests just to be sure. If they fail again the same way then do some of the resistance tests that I suggested and post the results.

Hmm, Minnesota isn't too far from Iowa....My sister in-law lives in St. Paul on Portland Ave. and says we don't visit her enough.... :smile:

ROD, were you planning on taking a test meter or a gas can?

Rod, joeh100:

Last night I brought the CCRM module box inside the house to keep it warm. I parked the car outside in the cold temperatures overnight (20 degrees). This morning I connected the CCRM module box back up to the car. The results saw the delay for "those fans to turn off" INCREASE to about 3 minutes ! ! ! !

Usually it's around 5 - 40 seconds.

Does this temperature test eliminate the CCRM module box from being my problem???

This morning I also retested pin-24. Now I get 12 volts at key-on fans on, and 12 volts at key on fans finally off...most of the time. I also got some very low readings similar to my 11/02 post. I am skeptical. I could be having a bad testing day, but I doubt it. I repeated this test this morning about 6 times.

(joeh100, I will review your previous posts and reply with a test plan for your latest requests)

thanks,
Rick

I reran three of the five requested tests during my lunch break today.

Pin-5: inertia fuel shutoff
key off: 1 mVolts <-----same value as previous test
key on fans on: 12 volts <-----same value as previous test
key on fans finally off: 20 mVolts <----this was 10 mVolts on the first test



Pin-15: ground
with red meter lead on battery positive post and testing for DC volts
key off: 12 volts
key on fans on: 12 volts
key on fans finally off: 12 volts

with black meter lead on battery negative post and testing for DC volts
key off: 0.8 mVolts
key on fans on: 44 mVolts
key on fans finally off: 14mVolts

with black meter lead on battery negative post and testing for resistance
key off: 1.6 ohms
key on fans on: 110 ohms
key on fans finally off: 35 ohms

joej100, I apologize for an invalid test that I posted on 11/02/06 for pin-15.
Today’s test for pin-15 should cover all the bases. Sorry about this mishap.


Pin-24: POWER TO PCM
key off: 1 mVolt
key on fans on: 12 volts
key on fans finally off: 12 volts
Pin-24 test results today also were different than what I posted on 11/02/06. I want to say that it’s user error here. Pin-24 should be 12 volts. Whether pin-24 was a good test or bad test, the fans would still run for awhile.


The good news is that I am going to pick up a used CCRM module box in about an hour here. I am going to bring my test meter with and confirm the diode test with pin-5 and pin-15 has a value of .5 ~ .7 unlike my current CCRM module box which is 0.L both ways.

Rick

A lot of thing are different when a car is cold. It has to idle higher for longer to warm up and other things too. This does not really eliminate the CCRM yet.

pin 15 and 24 seem to be ok now.

pin 5 still verifies the fuel pump is running at the same time the fans are running.

Retest pin 18, with meter on bat neg. With the fuel pump relay disengaged you should be getting 12V here. If your not then there's a problem. Also easy to verify with the resistance test I mentioned.
This is the last thing I see that could be causing a problem in the CCRM besides the diode.

Les us know if the new CCRM works though.

The resistance test between pin-12 and pin-24 on the CCRM module box was 0.3 ohms.

The resistance test between pin-12 and pin-24 on the CCRM wire harness was 0.4 ohms.

The resistance test between pin-17 and pin-12 on the CCRM module box was 87 ohms as expected.
The resistance test between pin-17 and pin-24 on the CCRM module box was 88 ohms as expected.

That's all I got for test data. Now here are the results for the spare parts I tried at the local salvage yard.

I tried a CCRM module with the same exact Ford numbers of 101 on the top row, then a big letter R, then F6SF-12B577-AA: nothing improved. The fans still turned on and the car would not start until the fans turned off. The diode test at pin-5 and pin-23 was 0.L both ways on this spare part.

I tried a CCRM module with the Ford numbers of 101 on the top row, then a big letter R, then F48F-12B577-AA: nothing improved. The fans still turned on and the car would not start until the fans turned off. The diode test at pin-5 and pin-23 was 0.7! But nothing improved. :-(

I tried a THIRD CCRM module with the Ford numbers of 101 on the top row, then a big letter R, then F48F-12B577-AA: nothing improved. The fans still turned on and the car would not start until the fans turned off.

Only the very first CCRM module from the salvage yard had the exact same Ford part numbers. The second and third CCRM module from the salvage yard were almost identical to the entire Ford numbers as compared to my original CCRM module....except the first part of the last number was different. I typed F48F as that first part...I am going by memory. The numbers of 101 on the top row, then a big letter R, then F6SF-12B577-AA are the exact Ford part number as found on the original CCRM module.

Well.
Well.
Hhmmm.

I either got three bad CCRM modules............ or it's something else on the car causing problems. This Monday, I am going back to the salvage yard and will be trying to replace my car's computer (PCM/ECM) with one of their spares.

We'll see what happens!

thanks, Rick

Wow, I really expected a good CCRM to fix this, and I would doubt you got three bad CCRMs.

One test from a few posts ago piqued my curiosity:
"Pin-5: inertia fuel shutoff
key off: 1 mVolts
key on fans on: 12 volts
key on fans finally off: 10 mVolts"

This has me wondering if for some reason, when the PCM is attempting to activate the fuel pump to prime the system, the fans are turning on, loading the signal, and somehow setting up an oscillation. Mitsubishi had issues with a bad batch of electrolytic capacitors in their ECMs that would cause goofy things like this. I have not heard of Fords having a similar issue with faulty caps though. But, I'm not working in the automotive industry either.

An electrolytic that is going high in Equivalent Series Resistance (ESR) could set up an oscillation or R-C delay circuit that is quite temperature sensitive though. Such an oscillation would be difficult to detect using a DMM, even on the ACV setting. You'd likely need an oscilloscope to pick it up.

I'll be interested to hear what the alternate PCM does for you. I hope we are not sending you on a completely wild goose (or is it grey duck in MN?) chase.... It would appear that our record is not too good currently.

-Rod

Any batch of components could be bad, but the infamous bad batch of electrolytics out of Taiwan was after 2000 if I'm not mistaken.

Doohhh!!! Here's something I meant to mention earlier. Check the resistance between pin 5 and all fan pins (1,2,6,7) on the connector going to the CCRM (not the CCRM, but wires coming into it with key off). Bad wiring in the harness could actually be connecting the fans to the fuel pump. They are coming off of the same connector. Oh yea, check resistance from all these pins to bat. neg. for comparison. Resistance from (5 to neg.) + (6 or 7 to neg.) should = resistance of (6 or 7 to 5).

He's obviously eliminated the CCRM but what about that bad diode ROD? You think spikes coming from the fuel pump could have damaged the PCM. There is a wire coming off of pin 5 back to the PCM. I'm not sure of it's function but it's probably for testing the fuel pump.

The spikes would of course be high voltage in the opposite polarity. Not very good for electronics. If he puts in a new PCM with the original CCRM and it still has the open diode then it could possibly damage the new PCM.


Some more ideas if the new PCM doesn't work. Again, I'm shooting from the hip now but what the hell.

Do you have diagrams for the fuel pump wiring? Anything else connected there that could have been damaged.

Try leaving the car out and warming the PCM with a hair dryer (not a heat gun) before starting.

I know it tested good but try heating the engine temp sensor before starting also to see if the PCM is actually causing the fans to run related to this sensor. Or put a potentiometer in line here and test the time.

This is really far fetched, but did you disconnect bat. yet. Maybe bad data is causing a flaw/bug in the programming.

We were having numerous issues with bad electrolytics with the Gen 1 Mitsu 3000GT/Dodge Stealth. That was model year 1991 through 1993, so there was a bad batch of caps at least back to the early 1990s.

The fuel pump system is wires, the inertia switch (mechanical switch) and the pump. It is possible that a bad CCRM could contribute to a damaged PCM, or vice versa. That is a good thought.

I'm gonna have to look around to see if I still have my dissected CCRM to see if it agrees with Rick's.

-Rod

Hello again to Rod, joeh100, and others:
I was away for the long weekend. I just got back.

Rod,
I was also wondering "WHY" to the following test results at Pin-5 (inertia fuel shutoff):
key off: 1 mVolts
key on fans on: 12 volts
key on fans finally off: 10 mVolts.

My "WHY" here is why did the voltage drop to 10 mvolts once the fans turned off?, and would the voltage return to the proper 12 volts once the car is started since the fuel pump would need to turn on to continue supplying fuel to the engine?
I am go to assume "yes" to my last part of my question above...but we’ll see after testing this.
I will test Pin-5 again but add one more VOLTAGE test result of "key on/fans finally off/engine running".
key off: 1 mVolts
key on fans on: 12 volts
key on fans finally off: 10 mVolts.
key on fans finally off and engine running: ??? volts

joeh100,
I will run the following resistance tests this evening with key OFF:
1) resistance between CCRM wire harness pin-5 and pin-1 (low electric cooling fan power)
2) resistance between CCRM wire harness pin 5 and pin-2 (low electric cooling fan power)
3) resistance between CCRM wire harness pin 5 and pin-6 (high electric cooling fan power)
4) resistance between CCRM wire harness pin 5 and pin-7 (high electric cooling fan power)
and
5) resistance between CCRM wire harness pin-5 and negative battery post
6) resistance between CCRM wire harness pin-1 and negative battery post
7) resistance between CCRM wire harness pin-2 and negative battery post
8) resistance between CCRM wire harness pin-6 and negative battery post
9) resistance between CCRM wire harness pin-7 and negative battery post

Oh yes, one more tidbit of information. I already tried heating up the ECT sensor with a hair dryer to see the effect it had on the "delay time for the fans to turn off" - it had no effect. I also put the hair dryer in the air intake tube (where the air filter is found) and supplied very warm air up into the air intake into the motor - it had no effect on the "delay time for the fans to turn off".

I did try heating up the PCM on another test which had no effect. However, it seemed like the heat really could not get to the "smarts" of the PCM itself. Just the wire harness is all I could get at to warm up. Therefore, I am going to take the PCM out one night to see if it has a confirmed effect on the "delay time for the fans to turn off".
I will conduct this test by 1) disconnecting the negative and positive lead on the battery, 2) disconnecting and removing the PCM, 3) keep the PCM warm in the house, 4) reinstall the PCM the next morning when it’s cold out, 5) connect the positive and negative lead on the battery, 6) and turn the key from "off" to "on" and see what happens to the delay time. Right now it has gotten back to 50 degrees again. The delay is only 7 - 9 seconds. I will need to wait until the temperature gets colder, let’s say to around 20 degrees, before I can do this test. The delay at around 20 degrees can be up to 2 or 3 minutes!!!!.
Once I run this test and the delay is only 7 - 9 seconds, then I’m assuming the PCM is the problem.
or
if the delay is still long from around 40 seconds to 2 minutes, then I will assume the PCM if fine, and then I will test all the positive and negative inputs at the PCM itself to see which one is not showing up at when I turn the key from "off" to "key on".

Thanks again for everyone’s time for helping, and also the EXTRA STEPS trying to avoid damaging any new components that may be placed into the overall picture. Rick

Hey, Rick. Did you ever order the CD manual off of ebay? If so what did you think of it? I'm thinking of ordering one for my car.

Hello again to Rod, joeh100, and others:
I was away for the long weekend. I just got back.

Rod,
I was also wondering "WHY" to the following test results at Pin-5 (inertia fuel shutoff):
key off: 1 mVolts
key on fans on: 12 volts
key on fans finally off: 10 mVolts.

My "WHY" here is why did the voltage drop to 10 mvolts once the fans turned off?, and would the voltage return to the proper 12 volts once the car is started since the fuel pump would need to turn on to continue supplying fuel to the engine?
I am go to assume "yes" to my last part of my question above...but we’ll see after testing this.
I will test Pin-5 again but add one more VOLTAGE test result of "key on/fans finally off/engine running".
key off: 1 mVolts
key on fans on: 12 volts
key on fans finally off: 10 mVolts.
key on fans finally off and engine running: ??? volts

Yes, if anything is going to make sense here, you'll have to see +12V on pin 5 with respect to ground when the engine is finally running. If you have access to an oscilloscope, this would be an interesting signal to scope out.

-Rod

joeh100, Rod:

Here are the latest test results.

DC voltate test for Pin-5 (inertia fuel shutoff) with the black meter test lead connected to the negative battery post:
key off: 1 mVolts
key on fans on: 12 volts
key on fans finally off: 10 mVolts.
key on fans finally off and engine running: 12 volts <------- looks good !!!!!!!!!

Rod, I believe Pin-5 above is showing the correct voltage........right?


With key OFF:
1) resistance between CCRM wire harness pin-5 and pin-1 (low electric cooling fan power) was
1.8 ohms
2) resistance between CCRM wire harness pin 5 and pin-2 (low electric cooling fan power) was
1.8 ohms
3) resistance between CCRM wire harness pin 5 and pin-6 (high electric cooling fan power) was
1.1 ohms
4) resistance between CCRM wire harness pin 5 and pin-7 (high electric cooling fan power) was
1.1 ohms
and
5) resistance between CCRM wire harness pin-5 and negative battery post was 0.9 ohms
6) resistance between CCRM wire harness pin-1 and negative battery post was 0.6 ohms
7) resistance between CCRM wire harness pin-2 and negative battery post was 0.6 ohms
8) resistance between CCRM wire harness pin-6 and negative battery post was 0.4 ohms
9) resistance between CCRM wire harness pin-7 and negative battery post was 0.5 ohms.

joeh100, I really am unsure what results would be favorable for the above 9 tests. Let me know what this outcome means when you have time.

joeh100, you asked about the cd manuals of ebay. Well, if you want tons of information to read, study, learn, reference, print, get lost with, data overload...then I easily say without a doubt these cd manuals kick @$$. I just got mine today. They are loaded with tons of information, pictures, diagrams, pin-outs, testing steps, troubleshooting trees, etc. Plus all this information is for electrical, mechanical, emissions, etc. I cannot say enough about the cd manuals. They go in great detail too. I got mine for only $4 each. I got one for my 1997 Taurus and my 1995 Ford F150. When I searched eBay for these cd manuals, I got lots of sites selling these cd manuals. I will find my order information tomorrow and let you know which merchant I dealt with.


Back to the Taurus starting mystery. I am thinking that with the warm weather again, I won’t be able to conduct my "car outside in cold weather and pcm inside in warm climate" test very soon. Therefore, I will probably go back to the local salvage yard, and search for a 1997 Taurus GL pcm with the same calibration code. I can try it on the spot for a very small fee. It’s worth our time to try this.
Could you guys get back to me by Friday if my car could possibly damage another pcm or not with what we have tested so far?


I don’t mean to talk (type) anyone’s ear off, but I have been thinking (and learning) about my car and how to summarize the past weeks of testing.
Other people have said to replace the CCRM to "fix the fans and have the car be able to start again"...I believe them that a new CCRM solved their problems because in their case, the PCM relay was probably bad in the CCRM, therefore no power was supplied to the PCM which meant no PCM involved in the picture and this would cause the fans to turn on, and car not to start neither. Remember, the fans will run if the PCM harness is disconnected (or with no working PCM at all in the picture).

Yet other people have said to replace the PCM to "fix the fans and have the car be able to start again"...I believe them that a new PCM solved their problems too because a bad PCM won’t do its thing and with no PCM involved in the picture, this would cause the fans to turn on, and car not to start neither. Remember, the fans will run if the PCM harness is disconnected (or with no working PCM in the picture).

In my case, I have:
1) no injector pulse signal while the fans are running
2) no spark at the spark plug while the fans are running
3) no difference with the CCRM brought into a warm house overnight last week when it was cold
4) pcm power leaving the CCRM and going to the PCM while the fans are running
5) absolutely no OBD-II communications to my data scanner while the fans are running.
6) the car is eventually still able to start; the car is not a "no start condition" because the car will eventually start, and once started it runs fine.
I do not want to focus our attention on the part that says "while the fans are running"...it’s just that the fans are a great indicator when, I believe, the PCM decides to all of a sudden show up in the picture for some reason and do its thing (supply a signal to the fan relay in the CCRM thus turning the fans off, supplying injector pulse signal and spark to the spark plugs thus allowing the car to start easily, and supply all kinds of OBD-II data to my scanner).

So to finish here, yes I will stop typing, I either have a:
A) bad PCM
or
B) bad or missing signal from the car that is not getting to the PCM which is preventing the PCM to come to life or "turn on"...and by "missing signal" I mean a missing power or missing ground signal into the PCM.

How’s that for a summary of what has happened so far?
thanks, Rick

Thanks for the info on the CD's. I will definately be ordering one.

Your test seems to indicate no problems with external wiring from CCRM in the fuel pump or cooling fan wiring. There is a .3 ohm discrepency though. Can you disconnect the plugs at the cooling fans and measure the resistance from pin 5 of the CCRM to pins 1, 2, 6 & 7 again just to be sure. With the fan plugs disconnected your meter should show OL with all of these tests.

Assuming the above does show OL then I would say there are no problems with the CCRM (except the diode, did you fix this yet) or the external wiring or components after the CCRM. Your problem would have to be with PCM or inputs to the PCM.

The PCM does drive the ignition and the fuel injectors directly doesn't it. There are no external modules between them are there?

There is a rare case in electronics where you have to replace 2 components at the same time. If you don't one could damage the other and vice versa. I wouldn't worry about this just yet. Assuming you don't have an O'scope, I would pay the fee you mentioned and test with the new PCM. A bad PCM was my original "guestimate", but I have to admit I am perplexed by your problem.

Good luck, and if all else fails you may want to reconsider my plan for insurance fraud. :evillol:

I have a concern though with the idea that having the PCM unplugged, the fans still run. Are you able to tell if the fans are running in high or low speed? Did you perform this check with any of the other "spare" CCRMs to see if they cause the fans to run with the PCM unplugged? I would suggest checking that before trying a "spare" PCM. The high speed fan relay is driven directly by the PCM. The low speed fan relay is controlled by a solid state controller which is controlled by the PCM. About the only way either fan could run with the PCM disconnected is if one or both relays are faulty and sticking closed for some amount of time, or there is a wiring issue between the PCM and the CCRM. If the low speed fan is running, then a faulty solid state relay controller inside the CCRM could also cause the issue.

As joeh100 eluded to before, this could be a case of two bad components, the CCRM and the PCM. Sort of a chicken or the egg scenario though. If the PCM caused the CCRM to fail, then you may now have three bad CCRMs.

It would be nice if you could find a good friend with a 1997 Taurus. Get a fresh CCRM and install on the working Taurus. If it works there, then tried a "spare" PCM on their car. If that also works, swap them both into your car.

Also, if you are friends with a local shop or dealership, see if you can get your hands on a breakout box for the PCM. This will allow you to monitor the inputs and outputs without cutting wires to the PCM or pulling terminals from connectors.

-Rod

Rod,

I did not check for low fans -vs- high fans at all.
I did not disconnect the PCM during any of the three other CCRM's.
I do not have a friend with a 1997 Taurus nor an opportunity for a break-out box.

I'm 0 for 3 here. :-(

Maybe if I can get lucky where a different used PCM solves everything (no fans, no delay in starting) then I'll stop and purchase that PCM.

Otherwise, I will wait for cold weather again so I can try my test of bringing into the house the PCM itself overnight to keep it warm while the rest of the car sits outside in the cold weather.

If that doesn't prove anything, then maybe I need to bite the bullet and purchase a new PCM at my local Ford dealership ($280) and pay the 1 hour of labor ($75/hour) to install/flash the PCM, and at the same time also purchase a new CCRM ($150) at the same time. Installing the PCM is simple, I just don't have the ability to program/flash the new PCM...so I'm stuck going to the local Ford dealership...a.k.a. local Ford stealership. I also will be left with a good enough spare CCRM for any future Relays going bad (fuel pump, a/c, pcm, fans) that are not related to my current issue.

How's that for a plan?

Actually, since the PCM might be damaging the CCRM, I could probably just purchase the new PCM and see what happens. The CCRM cannot be damaged anymore at this point anyway. I could always then purchase the CCRM if needed. This is relying on the fact that the current CCRM could not damage the new PCM.

joeh100, I will still follow through with our latest test ideas with the fans disconnected too.

Thanks.

joeh100,

I got 0.L for all the tests as you had requested with both fans disconnected.

I also brought the PCM into the house and placed it into the refrigerator overnight. It will be VERY interesting if the delay comes back or not.

Wait, I didn't know the fans were still running with the PCM unplugged. Was this with the PCM connector unplugged or with the CCRM connector unplugged?

Based on your earlier tests it is the low speed that is activating.

With the connector unplugged do the fans run constantly or do they shut off like normal after an amount of time. If they shut off after a certain amount of time and the PCM is unplugged then this totally eliminates the PCM. That would be good news. But, if they run constantly this could be normal if the relay driver has it's own pullup resistor.

You could test by breaking the connection to the PCM and tying the #14 wire to either + or - on the bat. One shoud make the fan run and one should make the fan go off. You should probably put a resistor in line (1K ohm) to be on the safe side though, because we don't have enough info on the relay driver. If it doesn't work with the resistor then it is probably safe to go direct. You should make sure the PCM is disconnected.

I just noticed something else very interesting. The fuse symbols are not all the same on the diagram. Some of these aren't automatic reset circuit breakers are they? That's definately worth checking out.

joeh100

Wait, I didn't know the fans were still running with the PCM unplugged. Was this with the PCM connector unplugged or with the CCRM connector unplugged?

To answer this: the fans run when the PCM wire harness is disconnected from the PCM itself while the CCRM is still connected. The fans do not run when the CCRM is disconnected.


With the connector unplugged do the fans run constantly or do they shut off like normal after an amount of time. If they shut off after a certain amount of time and the PCM is unplugged then this totally eliminates the PCM. That would be good news. But, if they run constantly this could be normal if the relay driver has it's own pullup resistor.

To answer this: I disconnected the PCM only to confirm that the absence of a PCM (or the absence of a PCM signal to the CCRM) that the fans turn on and stay on...which they did with the PCM disconnected. I did not run this test for a long period of time to see if the fans would turn off.


You have mentioned to disconnect the PCM, then connect pin-14 on the CCRM to battery + or battery -. Is this with the CCRM disconnected too?

When you talk about resistors, 1 k ohm, automatic circuits, breakers...I don't understand that stuff. Sorry about that. Remember, I am the pit gopher here and you guys are the intelligence behind the plans. :-)

Rod, joeh100:

This is interesting. The temperatures have been warm here lately for me to test by leaving my car outside/pcm inside the house. So, what I did instead was leave the car in a warm garage, and put the pcm in a 20 degree environment inside the house. This morning I quickly connected the PCM back into the car, and the DELAY TO START THE CAR WAS QUITE LONG...about 40 seconds!

I will confirm this by leaving my car outside in the cold temperatures when they arrive, and bring the PCM in the warm house overnight. I am willing to bet that there will be a very, very little delay starting the car.

So, I'm thinking at getting a new PCM. Should I get a new CCRM too? I am thinking I do not need to get a new CCRM too unless the schematics show a way that the CCRM could damage the new PCM. Any input on this?

joeh100, Let me know if I should test pin-14 to battery + and battery - without using a resistor.

Tomorrow, I will be going to a local salvage yard, and try to find an OEM PCM for my car with the same part #: F7DF-12A650-EB with NXZ1, and the calibration #: 7-10B. If this used PCM works...great. I'll just buy it...DONE. If I can't find a PCM that works out, then I feel I would/should go with a Ford OEM PCM since this is a critical part of the car.

I see online that some PCM's can be ordered with the correct flash, but the same website states that the VIN number needs to be programmed at time of install. Not sure what this is all about, but I will let the Ford dealership install and program a new PCM (if I can't fiind an OEM PCM).

Thanks.

To answer this: I disconnected the PCM only to confirm that the absence of a PCM (or the absence of a PCM signal to the CCRM) that the fans turn on and stay on...which they did with the PCM disconnected. I did not run this test for a long period of time to see if the fans would turn off.


This is a very important test. If the fans shut off after a while like they normally do then this totally eliminates the PCM, But if the fans never shut off then this could be normal since they have no control signal.

You can pick up a 1K ohm (1/2 Watt) resistor from Radio Shack. Just ask the nerd behind the counter. You may also want to pick up a set of gator clips leads, they can come in handy when troubleshooting.

I will confirm this by leaving my car outside in the cold temperatures when they arrive, and bring the PCM in the warm house overnight. I am willing to bet that there will be a very, very little delay starting the car.
If this test confirms your previous test then it sounds like problem solved. You may want to still do the pin 14 test to confirm proper CCRM. Also get the diode replaced if you haven't so far.

After about 100 posts, the "fridge" test seems to have nailed it down. Damn good idea if you ask me. Wish I had of thought of it.

joeh100,

If the diode is NOT fixed before I install the new PCM, can the CCRM that contains this bad diode damage the new PCM?

The tests I will conduct this evening:

1) disconnect PCM wire harness, leave the CCRM connected, turn key "on" which will cause the fans to turn on...and wait several minutes to make sure the fans continue to stay on

2) I will buy a "1K ohm (1/2 Watt) resistor from Radio Shack", disconnect PCM wire harness, leave the CCRM connected, key "off", and jumper wire-14 to battery (+) and battery (-) to confirm turning the fans off and on.

joeh100, please confirm if I got the test steps correct... and also about the possibility if the bad diode can damage the new PCM.

Thanks again.

Rick

A note of caution on the pin 14 test. It is unclear what level the solid state relay controller is expecting, battery voltage or logic level such as 5V or maybe even 3.3V. If you limit the current with a resistor such as 1k, you'll probably be okay, but by all means don't attempt to connect that straight up to the battery. I agree with the recommendation from post #80.

I would expect that Ford conformal coats the PCM and CCRM, but if not, it would interesting to reflow all joints, or at least any that appear suspect, to see if that fixes anything.

When I purchased my 1998 Taurus SHO, I found after a couple weeks that randomly the radio head unit backlighting would shut off. The radio continued to work and the display was fine, just the button illumination went out.

I opened the deck up and inspected the solder joints and traces under my magnifying light, nothing obvious. I traced the illumination circuit and reflowed all joints, even though none looked suspect. I never had the solder pull away from the joint as is common with cold joints, but for 2 years afterwards, I never had another illumination issue. Must have been a cracked via/feedthrough somewhere I suppose.

-Rod

Assuming a BJT is driving the relay then a 1K ohm resistor should limit the current to about 13 mA. If however, the driver already has a current limiting resistor this may not even work. It's hard to say without having access to the CCRM. Did you see if the fans continue to run with the PCM disconnected. That should mean that everything is OK.

Anyway, connect one side of the resistor to pin 14 and the other side to the bat. Make sure the PCM is disconnected.

I wouldn't chance a new PCM without replacing the diode. If you take the CCRM to Radio Shack and show them the diode then they may replace it for a small fee. It really depends on the Radio Shack though. If you have an Amateur Radio club in your area they would probably solder in a new diode for free (if you supply it) and maybe even retouch all the joints for a small fee.
If the board has conformal coating, acetone will cut right through it (If it's not silicone based).

Sounds like you might be treating the symptom and not the problem. I ran into a similar situation with the CCRM on my Taurus. Swapped several CCRM and other components without a change in behavior. I ultimately discovered a bad ground between the CCRM and the frame. (was a bad ground plug that terminated on the frame right next to the CCRM!!). The current drop caused the multiple relays to chatter (whirring sound) and prevent the fuel pump and PCM from energizing. Do a wiggle test on the numerous ground lines in the car while running and see if the engine reacts...if so, you've found your problem. Hope this helps!

Pishmael, thanks for the ideas.

You had stated
Sounds like you might be treating the symptom and not the problem. I ran into a similar situation with the CCRM on my Taurus. Swapped several CCRM and other components without a change in behavior. I ultimately discovered a bad ground between the CCRM and the frame. (was a bad ground plug that terminated on the frame right next to the CCRM!!).

Correct me if I'm wrong, but I've "hopefully" eliminated the possibility of a bad ground to the CCRM by the following:
I checked for resistance between Ground Pin-15 which seems to be the only ground for the CCRM and the frame of the car and got the following (see post #31):
key-off: 0 1.9 ohms
key on fans running: 110 ~ 140 ohms
key on fans finally off: 22 ohms.

and

I jumpered a wire from the battery negative post onto the wire going to pin-15 at the CCRM.

and

I do have fuel pressure too.

None of the above tests/experiments prevented the fans from turning on when the key was turned from "off" to "on".

Would you agree the above could eliminate a bad ground problem such as yours?

Thanks.

joeh100,

Here are the results from the latest two tests.

1) disconnect PCM wire harness, leave the CCRM connected, turn key "on" which will cause the fans to turn on...and wait several minutes to make sure the fans continue to stay on

2) I will buy a "1K ohm (1/2 Watt) resistor from Radio Shack", disconnect PCM wire harness, leave the CCRM connected, key "off", and jumper wire-14 to battery (+) and battery (-) to confirm turning the fans off and on.

Test 1 had the fans running continuously for many, many minutes.

Test 2 did not turn the fans on when wire-14 was connected to either battery (+) or battery (-) while using the resistor inline. The fans stayed off the entire time during Test 2.

About your comment of replacing the diode in the CCRM...well...I have no idea what component on the CCRM board would be the diode that needs replacing. I will take the CCRM apart this weekend and trace pin-5 onto the circuit board and see what I find. What does a diode look like to begin with?

I feel very confident soldering any component to a circuit board as I have done so many times in the past...I just need to find out what part to replace. :-0

Thanks.

The diode will most likely be a small black cylinder with a white or silver band around the circumference on one end. The leads will be axial (one out the top of the cylinder, one out the bottom). The diameter of the cylinder will probably be around 2 mm.

The circuit board will most likely be at least 2 layers so you need a decent soldering iron and good desoldering braid to avoid overheating the pads and causing them to lift. If you have a small hand drill, you may be best off cutting the diode off of the board, then trying to desolder the remaining leads or just drilling them out, then installing the new diode in the proper polarity/orientation. Once you have the diode out of circuit, test the diode again as well as pins 5 and 15 of the CCRM to make sure the diode was the issue.

-Rod

The diode will likely look like the component at the following link:
http://www.mcminone.com/product.asp?catalog%5Fname=MCMProducts&product%5Fid=N%2D94B7157

-Rod

Rick, on your earlier post, did you perform test 2 with the key off? The switch would have to be on to do this test. However test 1 seems to show the fans run continuously, which means the CCRM is most likely fine.
BTW you can reuse those resistors. Just solder to an LED for a test light.

The link that Rod provided shows a price of 8 cents for a diode. Don't expect that from Radio Shack LOL.

If you don't have good soldering skills then the hardest part of replacing the diode will be removal. The easiest way is to cut one lead on the diode. Next heat the joint while pulling slightly on the lead with pliers. Either use a little flux or apply a little solder during removal to get the joint to flow quickly without over-heating it. If you use desoldering braid from Radio Shack then apply a small amount of solder to get things flowing. Their braid doesn't contain flux. You could also cut the leads and then solder the new diode directly to those leads (quick and dirty, but effective). Make sure you remember how the original was oriented before removing it though.

Also as Rod mentioned, test the original diode in circuit before you do anything.

joeh100, Rod, others:

I found the only PCM out of 20-some in the entire salvage that was compatible with my original PCM. I installed it in my car on the spot, and the car had no delay starting ! ! ! ! ! (and no fans were running that I had to wait for neither). Hoo-ray ! ! ! ! ! !

I guess we finally have our answer to this saga! ! ! ! !

Most people would stop here and call it a day. Well, per your recommendations I have decided not to chance my good used PCM that I bought today with the old CCRM still in place because of the diode being questionable. In the meantime, I have taken out the GOOD used PCM that I bought today, and placed the original PCM (the PCM with the delay) back in the car.

I ran my car for about 15 minutes with the good PCM today before taking it out. The good used PCM still worked fine prior to taking it out, however, do you think any amount of damage may have occurred anyway? Just playing it safe and wondering.

This weekend my next step(s) is:
try to locate a CCRM where the diode test between pin-5 (inertia fuel pump) and pin-15 (ground) shows something other than 0.L.
- and/or -
take apart my CCRM this weekend and see if I can find "that diode" to replace that you guys are describing.

We have been at this for two weeks...why stop now! :-)

T H A N K S .... A G A I N !

Yippie!!! More good progress! This could be a great reference thread in the future.

There is a chance the new PCM could have been damaged by the fuel pump turning off, but I would HOPE that the PCM has some redundant protection for that. In the interest of saving money though, probably not.

However, since you only had one or two cycles of shutting off the engine with the good PCM, the amount of damage should be minimal. Like ESD damage though, degradation could occur and cause a latent failure, but that could be 10 years from now, assuming you fix the diode or find a good CCRM. Plus, if this acts up again, you'll have a good idea on where to start looking. :)

Congratulations, and thank your for your patience.

-Rod

Yippie!!! More good progress! This could be a great reference thread in the future.

"1001 Ways to Test Your CCRM" :)

I took apart my CCRM. I traced pin-5 onto the board. I found it confusing where pin-5 leads to on the board. I could not confirm the diode for pin-5. I did find two diodes total for the entire board. I tested both and one had 0.6 for a reading and the other had 1.3 for a reading. Now I'm really confused.

Question 1: shouldn't I find a diode with 0.L as a reading at the circuit board location like I get when I test at the pin-5/pin-15 locations?

Question 2: could the diode that I am seeking be in the relay itself?

Here's an interesting fact. The PCM that I found to solve my problem this past weekend came out of the same car that earlier (about two weeks ago) I retrieved a CCRM out of...this same CCRM with the same Ford part numbers also tested 0.L at pin-5/pin-15.

I plan on looking for a used CCRM until I found one that tests well at pin-5/pin-15 before buying it, or just ordering a new CCRM.

Thanks.

You can use your continuity test function of your DMM to verify if the diode you are seeing on the board is the diode for pin 5 to pin 15. The diode for those could also be a switching diode (the link I sent you earlier is a rectifier diode). A switching diode will be in a translucent red case with a black band to designate the cathode. See the image at http://www.partsexpress.com/pe/pshowdetl.cfm?&Partnumber=1N4148&CFID=1701335&CFTOKEN=79533117

-Rod

Rod, joeh100,

I just found another identical Ford exact part# CCRM today about an hour ago. I did the pin-5/pin-15 diode test, and I still get 0.L and 0.L.

That is three "used" identical Ford exact part# CCRM's that all tested the extact same at pin-5/pin-15 via the diode test. Are we sure there is a diode that should show 0.5 ~ 0.7?

The diode could be at the fuel pump itself and not the CCRM for your car. Depends on if the diagram we're usising is correct.

The diagram that was e-mailed around is from the factory Ford service manual for the 1997 Taurus. It should be the correct one. The diagram clearly shows the diode internal to the CCRM, but the diagram is not a schematic, but rather a detailed block diagram. There could be other components in the circuit I suppose that causes the OL reading.

Taurus1997, any chance you could take a couple photos of the top and bottom of the opened CCRM and post them or e-mail them to us?

It's probably safe for you to install the CCRM with the new PCM and drive the car in the mean time. :)

-Rod

Taurus1997, any chance you could take a couple photos of the top and bottom of the opened CCRM and post them
Yes this could help a lot.

I have no problem getting a good detailed photo on the top and bottom of the CCRM board. Thanks for the idea.

In the meantime, I have a question about trying to locate "that diode" for pin-5. I will look for the other kind of diode that Rod listed as a "switching diode". Can I be certain I am at the right diode (whether it’s a diode or a switching diode) when I simply use a continuity check with my meter from pin-5 and to either side of the diode that I am trying to locate? Is it that fool-proof? I would also like to know this for future reference too.

If it’s that fool-proof, I can find "that diode" by checking from pin-5 for continuity to every diode possible on the board until I FIND continuity to a particular diode AND the diode then tests 0.L both ways. I will THEN know I found the right diode to replace. Does this sound like a good plan?

Thanks again.

You can use a meter to check the diodes but just make sure they aren't crystal diodes or the meter will destroy them. I wouldn't think Ford would use crystal diodes though. You'll need an oscilloscope to test crystal diodes. THIS (http://www.allaboutcircuits.com/vol_3/chpt_3/2.html) web page will help to explain the general testing procedure. Just remember that diodes are basically one way gates for electricity. You should get a reading one way but not the other (usually at a ratio of 10:1).

Before we get too far with crystal diodes (oh no), could somebody answer if I'm correct about my diode location/testing theory in the previous post/thread #100. I would like to know so when I take apart the CCRM tonight to take pictures of it...I can possibly also hunt down the suspect diode at the same time.

And about crystal diodes...what do those look like?

I will post the pictures tonight too.

thanks, Rick

Can I be certain I am at the right diode when I simply use a continuity check with my meter from pin-5 and to either side of the diode
This all depends on whats between the diode and pin 5. Would need a schematic of the circuit to know for sure. If you are just testing the diode then pin 5 shouldn't be needed, as you're just testing the diode itself. Don't worry about the crystal (Germanium) Diode. Most likely they won't be used, but they are very small, usually less than 1/4'' long.

Rick, yes, using the continuity function to determine the correct diode is fool-proof, as long as you watch the resistance when you hear the continuity buzzer. If, for instance, you found continuity to a diode and the resistance from pin 5 is a few ohms, you may be measuring continuity to another diode through a relay coil. According to the detailed block diagram from the service manul, that should not be the case if the CCRM is unplugged from the wiring harness.

If measuring from pin 15 though, you may measure continuity to the diode across the PCM relay coil.

If you find a diode that measures continuity between one lead and pin 5, and the other lead to pin 15, you can rest assured that you have found the correct diode.

-Rod

...but just make sure they aren't crystal diodes or the meter will destroy them.
Where did you hear that using a meter to test a germanium diode will destroy it? I've never heard that, and have tested numerous germanium diodes without known failures (possibly latent failures, but never had one come back). I'd like to be aware of this for the future, but want to check the source before I change my ways.

FWIW, the link you posted does not warn against testing germanium diodes. In fact, it mentions what to expect for a reading when testing them with a meter.

-Rod

Where did you hear that using a meter to test a germanium diode will destroy it?
Well maybe 'destroy' is not the best word to describe it. What happens is that it completely ruins the diodes sensitivity, basically making it a wrong part for that circuit. This is especially important when testing radar circuits. It's a fairly well know testing procedure. I'll see if I can find anything regarding it on the net for you :)

Well I found this (http://www.tpub.com/content/neets/14188/css/14188_68.htm) for you. Notice the last line of "Testing Diodes with an Ohmmeter" it says "NOTE:This test should never be used to test crystal mixer diodes in radars. It will destroy their sensitivity." and right under that is says: "An oscilloscope can be used to graphically display the back-and-forward resistance characteristics of a crystal diode."

If I find more on line I'll post it for you :)

Interesting, thank you for the link. I guess I'll have to remember to use my Fluke 199C from now on to test any germaniums I come across.

-Rod

Ooops, now that I've looked at diagram 2-15 in the link you posted, it looks like I should have kept my Tek 454 scope. I don't think the Fluke has horizontal and vertical inputs.

-Rod

Is it a B series or a C series?

Hey everyone:

I said I would post pictures of the CCRM this evening....how do I? I got some really nice detailed pictures. The bottom left of my web page says "you MAY NOT post attachments". What do I need to do to change this so I can post attachments?

Thanks.

Go here (http://www.imagecave.com/) and upload the pictures. It is a free site. Then you just copy and paste to have pic here. Just copy the EZ code.

http://usera.imagecave.com/way2old/Sheriffcar.jpg

Is it a B series or a C series?

The Fluke or the Tek? The Fluke is a 199C (2 channel color, 200 MHz BW, and the software to go along with it). :)

-Rod

Yeah that is one suh-weet scope/meter :) I thought I read where the new B series has those inputs but I'm not sure about series C. I don't allow myself to read too much about those scope meters because I tend to drool to much on my keyboard :p

Here are the four pictures of my CCRM.

The first picture shows the bottom side of the CCRM circuit board.
The next two pictures show the same top side of the CCRM circuit board.
The last is simply the cover for the CCRM.

I have placed a RED ARROW in each picture where I have confirmed continuity between pin-5 and that particular place on the CCRM circuit board.

This should be interesting what is diagnosed here.

http://img1.putfile.com/thumb/11/31910084484.jpg (http://www.putfile.com/pic.php?img=4004807)

http://img1.putfile.com/thumb/11/31910084476.jpg (http://www.putfile.com/pic.php?img=4004806)

http://img1.putfile.com/thumb/11/31910084362.jpg (http://www.putfile.com/pic.php?img=4004805)

http://img1.putfile.com/thumb/11/31910084317.jpg (http://www.putfile.com/pic.php?img=4004804)

Thanks.

Those photos are very beneficial! It would appear that the diode between pins 5 and 15 was not included (D8). The diode symbol and reference designator D8 definitely indicate this would be for a diode. Have you checked for continuity from the corresponding D8 pin to pin 15? On the component side of the board, the corresponding pad appears to be on a ground trace, which is the function of pin 15, so I'm quite confident that you will have continuity to pin 15. This would indicate that D8 is the diode that shows up in the block diagram, and for whatever reason, was not included in your version of CCRM.

If you want to confirm that D8 would be the suspect diode, check for continuity between one of the four large solder connections for the K2 relay (connections on the underside of the board) to pin 11 and one to pin 18. If all these measurements checkout fine, then your CCRM does not include the diode we've been discussing in the thread on the forum. There are two possible reasons for this, either the diode was left off by accident, or the diode was intentionally not installed. I would expect the latter since at Ford, Quality is Job #1. ;)

If the replacement PCM came from the same donor car as one of the PCM's that you also have as a spare, make sure to use the two as a matched set. It is possible that, as joeh100 mentioned before, the diode has been incorpated into the PCM. If the donor PCM is of a different part number or revision than what you removed from your car, then you should use the CCRM from the same car to be on the safer side.

Thank you for providing those photos!

-Rod

Rod, joeh100, others:

Thanks for ALL your help and time solving this vehicle starting problem. It was nice finding people that would offer their time to help others. I learned A WHOLE LOT too about car diagnostics, testing, and troubleshooting. Taurus1997.

I learned A WHOLE LOT too about car diagnostics, testing, and troubleshooting.
That's probably the most important part!

And this thread may possibly help others understand why sometimes when they take their car to a shop for service, it takes longer than initially expected to properly diagnose a symptom that seems rather trivial in the beginning.

For many shops, it's a catch-22. If they shotgun an electronic part and it doesn't fix it, they are stuck paying for it and keeping it on their shelf. Or, if they send the car out the door thinking it's fixed, when really the symptom just chose not to exhibit itself at that moment, the customer will be irate that they just spent $600 on a repair that didn't fix anything. If they properly troubleshoot the problem, the customer bad-mouths them for taking 4 or more days to find the problem. In the process of troubleshooting, they may run into parts that don't seem to match the information from the factory service manual, and as you realized, the CCRM is not intended to be taken apart.

An automotive technician would have a very hard time determining that the suspect diode was not actually installed in the CCRM, unless they were willing to eat the cost of a potentially good part.

I've been on the technician side of that story, it's not fun! I much prefer my current job where I can admit to my boss blowing up a $65,000 piece of hardware and just be told, "Try to be more careful next time" or "Write a procedure to make sure that doesn't happen again." :)

-Rod