95 TS 3.8 CEL on - codes P341-P321-P123

[WelmoedJ]

Guys,
I need some guidance.
Last week exiting the highway and then idling the engine stumbled like it was running on 5 cylinders.

I checked OBD and got P0341 (Camshaft position sensor circuit), P0321 (Crankshaft position sensor fault) and P0123 (TPS circuit high input) according to Haynes, but according to EFILive 341 is Intermittent cam signal, 321 is 18x interrupt lost.
While the engine idles I took off the electrical connector of the fuel injector at cylinder 6. This didn't change a thing in the stumbling idle.
So the problem could also be a bad injector (car has 235000 Km on it).

Haynes advices to check the CKP sensor by disconnecting and checking Voltage across pins C and D. There is 11.8 Volts there. Next they advice to the sensor electrical connector at pins B and D while turning the crankshaft pully. Here's where I get confused.
If I check on the cable connector I guess I don't get info on the sensor.
If I have to check the sensor I have to reconnect the cable, but where do I check the signal at B-D for voltage drops?

Anybody can enlighten me here and advice on the sensor checking and if that the first thing to look at?

Welmoed.

[LMP]

NOw...did all these DTC appear on a sudden at same time...?
...if you have a TPS fault, you should be denied 4th gear, TCC and cruise control.. Can you check for these ?
If injector #6 is the only one, when disconnected, that does not change the stumbling, that is a possible culprit...but then, not related to the DTC.....

Cam sensor is used to synchronize the injectors and injectors will work in "random" default mode with cam sensor failure.
Crank sensor is for ignition timing but will also impair injection....eventually loss of one of the signals (I do not remmeber if 3x or 18x) will kill the inkjection, but I understanad you can run the engine... Crank sensor signals 3x and 18x are fed to the computer through the ignition control module....and it is frequently the cause of problems. At that age, a spare ignition module is a must...so I suggest you buy one new on e-bay (around 69$) D1977A , try it and in any case, keep for a spare if it does not solve the problem. It is under the three coil packs and easy to replace. COme back with results.

[WelmoedJ]

Originally Posted by LMP

NOw...did all these DTC appear on a sudden at same time...?
...if you have a TPS fault, you should be denied 4th gear, TCC and cruise control.. Can you check for these ?

You helped me last year with this, thanks again. And, no all those functions are still there (would have mentioned it if otherwise).

If injector #6 is the only one, when disconnected, that does not change the stumbling, that is a possible culprit...but then, not related to the DTC.....

I didn't think so either, however it's still on the check list.

Cam sensor is used to synchronize the injectors and injectors will work in "random" default mode with cam sensor failure.
Crank sensor is for ignition timing but will also impair injection....eventually loss of one of the signals (I do not remember if 3x or 18x) will kill the inkjection, but I understand you can run the engine...

Yes, I can run the engine, but I havn't driven the car after coming hoem with that stumbling engine.

Crank sensor signals 3x and 18x are fed to the computer through the ignition control module....and it is frequently the cause of problems. At that age, a spare ignition module is a must...so I suggest you buy one new on e-bay (around 69$) D1977A , try it and in any case, keep for a spare if it does not solve the problem. It is under the three coil packs and easy to replace. Come back with results.

I'll go for this as my first objective.
At least it's in a more convenient place if needing exchange.

So how about the issue of testing the output of the crank sensor described in the Haynes manual. As I mentioned in my first message I disconnected the cable to the sensor to test for voltage.
I got confused at the part "testing sensor signals" using a voltmeter and checking for 18 drops from 12V to 0V. One can't do that without reconnecting the cable. The manual didn't shine a light on where to retrieve those signals as one's not going to puncture wires just to read signal. My assumption is that there must be a point near the DIS unit as the cable runs that way, however I couldn't find the right colours.

Welmoed.

[WelmoedJ]

Originally Posted by LMP

Now...did all these DTC appear on a sudden at same time...?

Overlooked to answer to this one.
After I came home I didn't have the opportunity to immediately read the system.
In the time between coming home and receiving the reader I tried and started the car, with the obviously results (stumbling idle).

Once I got EFIlive and the ALDL reader I had all three error messages in the same readout.
Hard to say which one was first and if it has been alone at the first occurance. There has been a week in between noticing the problem and reading the codes. Car hasn't been driven in between.

Welmoed.

[Jrs3800]

I agree with LMP... You are looking at the ICM or the Crank sensor... as I have several 3800's here in front of my house I keep a couple of spare ICM's around... Over the last few years I have had a couple take a dump..

So with the codes you have and at the same time, either the crank sensor is intermittent or the ICM is having issues..

Do you by chance have any other 3800's in your household? The ICM's cross all of the 3800's from mid 92 through the last year or production..

[WelmoedJ]

Originally Posted by Jrs3800

Do you by chance have any other 3800's in your household? The ICM's cross all of the 3800's from mid 92 through the last year or production..

No, I don't have another TS 3.8. Keeping more than one car over here is quite expensive.
Fortunately I still can drive (my other car, which is an oldtimer and free of road tax).

I'm going to find an ICM since LMP already mentioned they go a lot.
I'll report back after having found and exchanged that part.

Welmoed.

[nicke66]

Originally Posted by WelmoedJ

I checked OBD and got P0341 (Camshaft position sensor circuit), P0321 (Crankshaft position sensor fault) and P0123 (TPS circuit high input) according to Haynes, but according to EFILive 341 is Intermittent cam signal, 321 is 18x interrupt lost.

Hello,
I do also drive a 95 TS 3.8 but as I have not so far experience the same DTCs as you I am not really able to help you. But I have some photos from the factory service manual that possible can guide you. P0321 is actually called "Spark reference circuit". P0321 does not illuminate the CEL.

DTCs are stored in the control modules for 100 ignition cycles, and there are also information about how often, when first time and last time they were stored! I am not sure if EFIlive is able to read this information, but the software I use is. I am using the DOS software a German TS owner wrote some years ago. It is available at: www.pontiac-interface.de/

DTSs:
http://picasaweb.google.se/PontiacTr...eat=directlink

[WelmoedJ]

Originally Posted by nicke66

Hello,
I am not sure if EFIlive is able to read this information, but the software I use is. I am using the DOS software a German TS owner wrote some years ago.

Hi,
Sorry for a late reply, very busy.
I know about the German's program. However nowadays there are almost no notebooks (laptops) with serial ports. Mine doesn't either.
That's why I am using EFILive4 with Moates USB interface.

Welmoed.

[WelmoedJ]

LMP,
Thanks for bearing with me.

I ordered an ICM and the mail probably lost it. Second unit came in the other day. I wonder if I got an ICM as the metal (aluminum) box has three connectors (red, white, blue) and is situated underneath the dash at the passenger side. IMO this is an ECM/PCM unit.

Since I have got this part, I swapped connectors and - not surprisingly - no change in stumbling running. I now have the old part hooked up again.

BTW: The Haines manual doesn't refer to an ICM. All I have found is an Ignition Module, living underneath the coils. Very peculiar that the pages Nicke66 refers to do mention an ICM.

So now I'm totally confused! Can you enlighten me in this regard?

Welmoed.

[Jrs3800]

Yes what you got was the PCM.. Its the only module with red, white and blue connectors..

The ICM( Ignition Control Module ) does reside under the coils... And the signals from the crank sensor and the cam sensor pass through the ICM to the PCM..

[WelmoedJ]

Your reply indicates a flaw in the Haynes manual
I'll now go for the real ICM.
Hopefully it doesn't take that long as with the PCM.

I'll report back after having received the ICM.

Welmoed.

[Jeffrv]

While waiting for Ignition module, check a couple other things: check PCM grounds for corrosion or broken wires( loctaed on a stud underneath the ignition module). Your TPS code (p0123) can also be caused by an open ground in circuit 808, sensore rturn. the TPS, EGR, Trans temp and ECT all share this circuit anf can backfeed. It is a unique ground circuit in that it is not grounded to the frame in the usual manner, but these black wires are specifically grounded internally in the PCM, at pin E5 in the blue connector. Also, open the 14 pin connector on the ignition module and check for poor connections or corrosion. I used contact cleaner then dialectric grease on mine.
Good luck
Jeff

[WelmoedJ]

Originally Posted by Jeffrv

While waiting for Ignition module, check a couple other things: check PCM grounds for corrosion or broken wires( loctaed on a stud underneath the ignition module). Your TPS code (p0123) can also be caused by an open ground in circuit 808, sensore rturn. the TPS, EGR, Trans temp and ECT all share this circuit anf can backfeed. It is a unique ground circuit in that it is not grounded to the frame in the usual manner, but these black wires are specifically grounded internally in the PCM, at pin E5 in the blue connector. Also, open the 14 pin connector on the ignition module and check for poor connections or corrosion. I used contact cleaner then dialectric grease on mine.
Good luck
Jeff

Thanks, Jeff.
I will check all these connections too.

Welmoed.

[WelmoedJ]

This is going to be a long, long thread....
Today received something that the sender (a company) calls the ICM.
However what I got is a tin can with two connectors that's supposed to go underneath the dash (not the ECM/PCM).
Still nothing to replace and try.

BTW: there seem to be two models of the ICM on that has "ears" for screws and one - I guess that's the one in my car - that has a different mount.

The Haynes manual only shows the eared one and the way to disassemble that.
I have looked at mine from top to bottom but can't find out how to disassemble.
Am I to take the coils off before I can get the ICM out?
I welcome suggestions as I don't want to destroy parts.
Anyone having a picture of the correct product, so I can show the supplier what I need?

Welmoed.

[Jeffrv]

Normally you do take the coils off first, but coils/ICM can be removed as an assembly if you wish. Mark and disconnect the spark plug wires, undo the 14 pin connector at the front, and remove 3 nuts under the module bracket, and lift off. The coils will then have to be removed, 2 screws per coil, lift straight off. For pictures, go on E Bay , search for pontiac trans sport ignition module, several listed there.
Jeff