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01 Caravan PCM follies.Long post!
Posted to Technical Tips Forum on 8/6/2009 28 Replies

I had this 2001 Chrysler Voyager (!) minivan which belonged to a non-revenue customer…(Read: My daughter's car!), after I got the usual call all fathers are familiar with…"Dad…my car...(fill in the blank), I am going to bring it over to the shop". Which meant not only I had to fix it for free and pay for the needed parts; I had to provide a spare vehicle so she could commute to work and also get her 7-years old daughter to school and back, for as long as it takes!

Checking the system showed a P0204, which meant cylinder #4 was misfiring (Injector circuit open), MIL on, and the usual shake of a dead hole. Noid light did not show any pulses, injector was accessible and an ohm check showed 12.2 Ω right on the money…+B to injector was present, and driver wire to the PCM's pin 16 was not open. The engine was of course a 3.0L.

Code cleared, and as soon as the engine started, it popped right back on…P0204. So the conclusion by what was obvious indicated a bad PCM…right…?!!

A rebuilt (used!) PCM from an aftermarket source was purchased, and was programmed by the seller according to the VIN I had submitted. It arrived, was installed, the van started…and bingo…a miss, and P0204…again! This time the noid light stayed on…and unburned gas was almost pouring out of the tail pipe. Coincidence…?!!

Did the same checks as before, PCM connector was disconnected and the continuity of the driver wire was checked again and made sure it is not open or grounded. Was it possible the new PCM was bad also and had the same problem? Could this be a pattern failure?! PCM was returned and another one was on the way. (Week 2)

Enter PCM #2…!!! Same M.O., same code, and the same misfire! Noid light on all the time…engine missing and running rich, gas (almost) pouring out of the tail pipe! Question: What the heck is going on?

Enter PCM #3 from another supplier…!!! But hold on…I am not going to make the same mistake again…or am I…?!

Is it possible the injector #4 is getting shorted after a few quirts? So…this time we pulled the whole wiper cowl assembly for access. We pulled the top of the intake out, removed the injectors. All six read 12.3 Ω give or take 0.1 or so. Hard decision, but I stopped myself calling Linder for 6 new injectors!

We also cut the injector driver's wire a few inches away from the PCM just to isolate the system…(of course it was soldered later on and connected). Meanwhile I used a test light, coming from the battery's +B , and went to the driver's wire at the injector connector, reached behind a few bracket, lines, tubes and such, grabbed the injector harness's multi-connector (close to the exhaust manifold flange!...hint…hint…), and started pulling, pushing, yanking and twisting it like a mad man. Lo and behold, at one instance, my test light did come ON…!!! With a little more effort, I could just wiggle it in a certain way and get the test light to come on consistently. Wow…is this sucker going to ground intermittently?!

Pulled the harness out [Injector harness], and it looked sorry. Unraveled the tape from the connector (or what was left of the tape) [Injector harness connector] and then saw what was causing the injector driver to go kaput! [Damaged injector wires].

New harness could be ordered by the dealer at $260.00…!!! So…my meticulous tech (Bob C) who is a genius for repairing burned and distorted connectors using any leftover crap, did a fine job repairing it professionally using wires from a discarded Hoppy trailer hitch connector that had come off a Dodge truck, saved for a day that was not supposed to come…![Repaired harness connector]

How this van was ever running with all of those burnt insulation and those wires touching each other was an open a question I never found the answer…but I did not care any more!

The third PCM went on…the injector driver wire to the PCM was reconnected but we used a noid light in place of injector this time. Started the vehicle which run with a miss, but the noid light was also flashing properly and was not dead (like the original PCM) or staying on all the time (like PCM's 1 and 2).

Crossing my fingers, we connected the injector #4's connector back in…it run much smoother than I expected and no miss. Cleared the codes again…and this baby was done.

Of course I did not make a claim on the PCM's (was not their fault)…so it cost me the price of 2 PCMs and hours of labor, headache, phone calls and frustration.

Guessing I am not the only poor sap who saw such problem on this ubiquitous van…I hope my case helps someone if you see unexpected PCM and injector problems down the road on similar type of van and engine.

And I was rewarded "Thanks Dad…by the way, it needs an oil change too…"…!!!

In my choices between punching someone or having a decent drink…I opted for the latter!

Isn't fatherhood grand?


Mohammad from Illinois

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