I was driving my 2002 Grand Caravan 3.3L home this afternoon and it was running fine. I stopped at a local store and left the engine running but when I returned to the van and started to drive away, the engine almost stalled and starting running erratically. Then the CEL came on. I pulled off the road and did the key dance so I could read the codes and it read P0202 which is the #2 cylinder fuel injector circuitry or something like that. I restarted the van and proceeded home since I was only a few miles away but during the drive, the windshield wipers & washers and the radio clock worked intermittently. The clock would blink on and off randomly and there was no response from the wiper switch except for the turn signals. If I left the wiper switch on, the wipers would occasionally work in delay mode. Then right before I pulled in the driveway the radio clock stayed illuminated and the wipers and washer worked normally but the engine was still skipping and rough.

I've read through some other stories of people who have the P0202 code and for some it was bad wiring, bad pcm, or a bad injector. Does anyone see a link between the #2 injector circuit and the wipers/washer and the radio clock??? It's weird that they all failed at the same time. Does the PCM control the wipers and radio clock? Sounds like I might have a bad ground somewhere that is only affecting these three circuits or maybe a bad PCM but I suspect the PCM has nothing to do with the wipers or clock. I thought only the BCM controlled these and the PCM controlled the engine functions.

Of course there is a blizzard out right now so I can't run any more tests until tomorrow but I'm super curious.

Thanks!

 

"I thought only the BCM controlled these and the PCM controlled the engine functions." That statement is correct and says it all.

A few possibilities. (1) Early 4th generation vans have been plagued with a poorly routed fuel injector harness prone to melting causing any number of injector and other engine related problems. Look for a large connector on the drivers side of the engine and follow it back behind the engine about 6 -10 inches. It usually melts in that area because it is too close to the exhaust manifold and poorly insulated form heat. Remove the insulation (or what's left of it) and inspect the wiring. The link? Only a theory but one or more of the wires in the bundle are shorting to ground and loading the electrical system effecting normally unrelated systems.
(2) Again, early 4th generation vans have a history of IPM (fuse box) corrosion problems found both internal to the box and/or external at the connections. Many electrical problems have been attributed to this gem of a box.
(3) Did you run though snow drifts and throw snow up into the engine compartment? May have inadvertently shorted something or spun the serpentine belt.
(4) Weak batteries or poor battery/alternator connections have caused many electrical headaches because they are easily overlooked or passed off as "nah, can't be that simple."
(5) Test injector? Us "backyarders" listen with a screwdriver touched to the injector and cup the handle to the ear. Should hear a click as the engine runs or you crank it. You may be able to feel the click. You could test the injector pulse from the PCM using a noid or test light. If it blinks the PCM is ok. You can check resistance through the injector windings. Compare readings of several injectors and determine if #2 is in spec.
(6) Yet another troublesome wire bundle is routed under the battery tray. Acid drips on it and eventually leads to severed wires.

 

Injector harness goes directly to pins on the PCM/ECM socket. It may of blew a driver or worse. Just a guess, but I know for a fact the harness goes strait to the PCM pins. It's actually like this on most computer cars.. A weird injector problem or shorted harness will blow a driver and cause all kinds of stuff. PCM has direct connections to BCM which controls these other items.

Note that by "direct connection" I mean a wire with no regulators or anything else on them, going from one computer pin to another or some analog component to a pin with no protection.

Computer problems I dare say are the hardest(more time more money) to diagnose than any other problems including compression and vacuum.. If you keep driving it you'll probably get a P0601, so don't start-up till you fix it.

 

Well interestingly enough, the problem has disappeared. I have a spare PCM from a 2001 Chrysler T&C. It's not completely compatible with my van because for some reason it can't control the EGR and throws the P0403 code but I still took it for a drive and the P0202 code never appeared. So I reinstalled the oem PCM and reset the battery and so far no codes and engine runs great. Wipers & radio clock work too. I drove the van for a good 30 minutes and the CEL never came on and no codes show up.

So.......... what do I do now???? I was driving in a blizzard yesterday when all this happened. I didn't blow through any snow banks but I wonder if snow got up in the engine bay and shorted something out. I can see road salt all over the motor and under the hood so snow and slush definitely spray up in there while driving.

I also examined the wire harness that leads to the injectors and it appears to be in good condition. While the engine was running I grabbed the harness and moved it around to see if it affected the motor but it had no affect at all.

I guess I'm going to have to wait for it to reappear or maybe buy a compatible PCM???

 

Clean and grease all grounds.. My most educated guess. It's a ground or something that changes with thermal or vibration differences that is probably electro-mechanical or next to something that changes tempature. I think there are <10 grounds total on C/GC/T&C and most can be reached without disassemble.

It could actually still be an injector or injector harness.. You can actually future-proof the harness by rebuilding it with better wire.. Better wire being better grade that handles higher temperature on it's shelding..