New problems

[Kristamarie]

I'm back

Car is running great...driving down the road and all of the sudden the transmission feels like it is jerking for a second. Like it is trying to go from 2nd to 3rd to 2nd. A 1/2 mile down the road and the CEL goes on. The next time I drive the CEL is off for two days and then it comes on again.

I am getting codes:
12 (the list lmp has does not show 12)
18 - Cam Crank error
31 - PRNDL Input Circuit
41 - Camshaft Position Sensor Circuit
66 - Low A/C Refrigerant charge (it is flippin winter?) not using A/C

It looks like it is some sort of sensor that reads speed, just replaced the crankshaft sensor last year.

Any ideas? I appreciate all feedback!!!!!

[LMP]

What year model and engine was that...again?...codes listed are 3800..
12 is code just to say computer is in diagnostic mode
66..not using A/C? YOu think? Each time you put heater on DEF of DEF/FLOOR mode, it kicks A/C in to help dehumidify the air so the defrost is faster. HOwever, in winter, as temperature goes down, refrigerant pressure lowers too low and the low pressure cut-out switch inhibits compressor operation. But...if engine runs and car is stationary or moving very slow in traffic, engine heat can rise refrigerant temperature and pressure to the point it can work again....To avoid unauthorised A/C operation in winter, I always disconnect the pressure valve, just beside radiator, passenger side.
dtc66 means improper refrigerant charge. Wait for summer....you will have to disconnecet battery for 10 min to clear dtc to try again for a/c operation

18 and 41.....to be investigated
31 : consistent with erratic 2-3 shift.
browse through www.avigex.ca/xport to dtc numbers for more info.

[Kristamarie]

Yes, it is a 3800...a 92' Transport

Went to pick up my daughter from Volleyball and the CEL was on all the way there...off all the way home...about a 4 mile drive one way.

Just started a new job 25 miles away, gotta figure this out before something really bad happens. I am in Michigan and we are having one heck of a winter. I don't want to get stuck on the side of the road.

Camshaft Sensor?
Throttle Position Sensor?

[Kristamarie]

I never thought that the A/C would also be a dehumidifier too, it makes sense.

[LMP]

Originally Posted by Kristamarie

I never thought that the A/C would also be a dehumidifier too, it makes sense.

Noticed all that water dripping under car in summer...? This is air moisture that condenses on the evaporator and evacuates. WHen blocked with debris or mildew, the passenger floor becomes rapidly more a lake than a mat. Cold winter air contains lot less moisture...
I highly recommend disconnecting the A/C low presssure switch during cold season
to avoid unnessary freak A/C operation . IN my other car, the a/c is acted ON by DEF button by a real hardware switch concealed within the heater console...so I removed it and then only the real visible A/C button has authority. HOwever on the Transport, this is done by the computer...so it has to be tricked like I said.

[Kristamarie]

Okay no longer getting dtc66, but I still getting 18-31-41 codes. I know you provided a link to the circuit schematic, but where do I find these circuits? I do not mind getting my hands dirty, but I just need locations or I'll be checking the wrong thing.

I am going to spend the $20 for new camshaft sensor, and I know where that is located. I just need to know where to find the PRNDL circuit. Would you please help?

[LMP]

dtc 18 and 41 : do you have other symptoms like stalling and bucking? As described, cam sensor is used to synchronize fuel delivery and is not a go-nogo item....
www.avigex.ca/xport/ckps.jpg
the water pump pully has to be removed to get at the cam sensor.

THe signal from transmission to computer is from a switch housed IN the transmission....but the conneceetor itself can be the culprit.
DOews the car still erratically shift 2nd and 3rd gear as you said in first post...or was that just a freak event?

[Kristamarie]

Went two days of driving no cel-no problems.

On my way home from work no cel, stopped for gas, cel. It felt like it will not go into OD, the rpms stick around 1800-2000 at 30-40mph. At higher speeds it feels like I am dragging butt, or trying to go into OD and out. So I got off the freeway and took the side streets home. Doesn't smell hot after stopping. I kept my sniffer open.

Then picked my son up from wrestling, a 3 mile trip driving 30-35 mph the highest, with cel on. When we get to the house and I drop my son off by the front door, standing still, in gear, it surges, almost a stall.

The car has 200,000 miles on it and I am betting the only sensors that have ever been changed, have been changed by me. I do not have a problem replacing them. I just need to know which ones first and praying it is not my transmission.

[Kristamarie]

This morning, after the car sat in below freezing temperature overnight, I warmed it up and drove my son to a wrestling meet. It is about a 10 mile round-trip drive, and no cel and no problems. I am really baffled.

What would cause this intermittent trouble? The weather? The temperature? We have had record snowfall here in Michigan, could it be the snow under the van hitting an exposed wire?

[LMP]

Originally Posted by Kristamarie

...could it be the snow under the van hitting an exposed wire?

That is just what I was to suggest....Defaulting to 2nd or 3rd gear is what happens usually as a way to ensure the car is roadable even with detected troubles...
THe transmission selector contacts are throuh a rectangular plug., while connands to transmisison are through the round plug.

I'd verify for accumulation of ice or salt around these and for integrity of cabling. Something similar had been reported before and chaffed wires had been found to be the problem.

[Kristamarie]

Been driving all around town today and no cel....tomorrow is supposed to around 40 degrees, so it might be warm enough to take a look at these connectors. Although there may be too much snow to drive one side of the van up onto a curb and get underneath her. I may have to take it to a garage and have them take a look.

I am still going to replace the camshaft position sensor, it probably has never been replaced either.

I do appreciate all of your input. I will post back when I have a solution.

[Kristamarie]

I took it to the shop to have them take a look at the trans connectors and replace the camshaft position sensor. The technician said that the timing chain needs to be replaced ($380.00). The sensor on the chain? has broke off.

I need some feedback.

[LMP]

Originally Posted by Kristamarie

..the timing chain needs to be replaced ($380.00).
The sensor on the chain? has broke off. .

that chain drive is rather sturdy..but ..at 200,000 miles, that is possible... and plausible with the cam error if it jumped a tooth ..or two ... it would be quite lazy then.....

WOudn't he mean the "tensioner" or "bender" on the chain has broke off..???..if so, how could he tell taht without opening the front of engine ??.
Well...at $380, parts and labour, that would be an honest price.

[Kristamarie]

Originally Posted by LMP

WOudn't he mean the "tensioner" or "bender" on the chain has broke off..???..if so, how could he tell taht without opening the front of engine ??.
Well...at $380, parts and labour, that would be an honest price.

That is what I thought...Timing chain cover, etc. to see. Isn't there a magnet or other device that is on the cam for the sensor to read? Maybe that broke off or chipped? At 200,000 miles and no other timing chain replacement, I do think it is about time for a new one before it breaks while I am out on the road. Still doing the same thing...CEL off for two days...CEL on for a day...really weird.

[Benesesso]

Easiest way to check the cam chain (timing chain) is to put a breaker bar on the crankshaft bolt-the one that holds the harmonic balancer on. You should be able to reach it easily if you remove the right front wheel. Now, you need a helper. Remove to oil fill cap from the front valve cover, and have your helper look inside the oil-fill hole. There are 2 valve springs you can easily see-one on each side. Slowly rotate the crank and watch the springs. You must find the point at which one of the springs (either one) just starts to move DOWN near its top, AFTER you have turned the crank (counterclockwise from the right side) a bit with NO spring motion. *IF* you're lucky the bolt won't start to unscrew. Now, rotate the crank clockwise and watch the spring. It shouldn't move until the slack is taken out of the chain. With a good chain you should only be able to move the end of the breaker bar a couple of inches before the spring moves back up. *IF* it moves as soon as you turn the bar, it means the cam is being rotated by the springs/lifters and the test is not valid. The chain WILL have some slack, so after a couple of inches of bar end travel the spring will move. But if the bar moves something like 6 or 8" (assuming a bar ~18" long), the slack is excessive and you'd best replace the chain AND the cam sprocket. The smaller crank sprocket will probably be fine.