Manager Forum

I have a 2001 grand caravan sport with a 3.3 seems to keep killing pcm.

Keeps giving tps, coolant sensor, a/c pressure switch and IAC valve codes. I have checked wiring harness and all seems to be okay.

Any help with this would be appreciated.

What do you mean? Sounds like reference voltage problems. How many PCM's have been murdered? What testing have you done so far?

Checked 5 volt reference to all sensors listed and all are ok seems to be losing ground but when i scan the vehicle all pids are ready correctly.Also keeps giving IAT code. have checked wiring from all sensors to pcm and all are ok.

So how many PCM's have been installed? Were they new or used?

3 new pcms

Wow! Odd that a poor ground would take out a PCM. Can you tell us exactly the codes involved and why you feel it's losing ground. I'll print off a wiring diagram in the meantime.

Also, when the PCM dies, what's the symptom and what testing was done then?

Another question. Were the new PCM's from the dealer or aftermarket? Also, how long do they last? Time frame of when they were put in.

The pcms are coming from chrysler dealer.After i put them in the vehicle will crank and run good for a few days.I drove the van 53 miles before giving vehicle back to customer last time.I had found at one of the injectors the wire casing was gone on both wires at the inj. plug thought that was it but 2 days later van is back.the first time it was here the codes were IAT coolant etc. voltage high reference but now the vehicle wont even turn over.Scanner will not communicate now pcm dead.Dont want to put another in until i figure out whats killing it.I read somewhere that a bad alt. may be a possibilty but seems to be charging ok when vehicle is running.

Well, at least it was dealer pcm's. Even those are reman.

The current dead PCM, do you have reference voltage now? Possibility that there is a short to power on that line? I know that coils on these often take out the PCM.

if i'm reading this correctly the van won't even crank over. is there a remote starter in the van? could there be an issue with the anti theft. i've also seen issues with alternators spiking causing pcm issues.

I wouldn't rule out an alternator either until I scoped the waveform. Leaky diodes will wreak havoc.

ricmorin wrote:Well, at least it was dealer pcm's. Even those are reman.

The current dead PCM, do you have reference voltage now? Possibility that there is a short to power on that line? I know that coils on these often take out the PCM.

Very True! We had an ECM last week from the dealer that wouldnt take the initial program flash. Frustrating

faulty reman units really drive me nuts. i usually find myself falling into the "it must be something else" pit. like i've posted before, i have no faith in any reman, even from the dealer. i've had dealer remans with old information still in them and have taken me down the "yellow brick road" before. how do you explain to the customer that you've spent all day chasing issues because of a faulty part that i installed.

Replaced ign. coil and van has done great.thanks for all the help and feedback.

The drivers they use for the coils are crap in those PCM's. Time will tell. Sounds like you nailed it. WooHoo.

Ive had a few of these harnesses be damaged due to acid and had to hard wire then connectors for this problem

thanks for posting the "hopeful" fix.