Chrysler Repair/'96 3.8L engine stalled, no spark, ECM bad?
'96 Grand Caravan, 3.8L, low mileage [~132,000 mi.] Car was driving fine... 'check engine' light came on, yielded 'Code 66-No CCD messages recieved from the Body Control Module (BCM) .... Per forum advice which said 'more often than not caused by faulty grounds', i wiggled loose BCM connector, [the one under the hood [ECM?], not the one under the dashboard], cleaned negative battery terminal - solved problem; light went out; cleared codes [except for 12 and 55, which was expected].
A week later, car started running rough, 'check engine' light came on, blinking, yielded: Code 43-Ignition coil #1, 2, or 3 primary circuits-peak primary circuit current not achieved within the maximum allowable dwell time. Code 43-Engine cylinder misfire-engine cylinder misfire detected in one or more cylinders. Advance's OBD ll said 'bad coil on #2 cylinder'. I replaced coil pack and plug wires, plugs in back [although none of the plugs looked bad]; 'check engine' light stopped blinking, but stayed on, engine still mis-firing...
Engine finally stalled some 60 miles later, going up a hill. Cranks freely, but will not start - i thought the timing chain broke, but the mechanic said, "There's no spark, must be the brain - take it to the dealer." [Can the ECM deteriorate like that - run poorly before it quits?]
Before i go through that hassle, $600 - $1,000, i see on the interweb i can order an ECM, pre-programmed to my vin, sent to my home, for $200... Thoughts? Is it worth trying to talk the mechanic into checking the wiring around the CCD bus and elsewhere as a possible cause?
The original answer was based upon there being "no spark". However if there is by chance spark then the fact that it died going up hill raises in my mind the possibility that you really only have a mixture problem (too lean) because of the sticking open of the exhaust gas recirculation valve (EGR). That could be why it won't start/why it died going up hill/doesn't show any fault codes. So find that valve which is located in a small pipe that branches off the rear side exhaust manifold, then notice that between the vacuum hose operated top piece and the body of the valve proper there is a flange that hides the valve stem. The stem has a slot into which the tip of a screwdriver can be inserted that allow you to then move stem back and forth. Put some solvent like WD-40 on the stem where it enters the valve body and then exercise the action back and forth. Then see if it will start and run.
The 43 code based on the blinking count is about the primary wiring circuits of the ignition system. That should prompt a detailed check of the wiring of the three primary coil circuits.
If OBD II readout at Advance using a plug-in code reader pointed to #2 I would wonder if it was directed to the #2 primary driver circuit (rather than to simply bad coil on cylinder #2, as that driver circuit is responsible for producing spark at cylinder 2 and 5).
That circuit is from pin 11 of the PCM To pin 2 of the coil pack plug on a gray wire. See what the resistance is between those to pins which should be less than 5 ohms or not. If it is less than 5 ohms, and that code were valid then replacing the PCM is a possible solution.
However, because of the cost involved I would prefer to get another readout with a plug-in reader before doing that.
Then also I wonder if the check engine light is 'on', what does the self-readout show using the ignition key. There should be some blinking and what is it?
Also, unplug the PCM (what you are calling ECM) and check that the resistance to ground of pins 10 and 50 of the plug are less 5 ohms. Finally, turn on the ignition switch and verify that you are getting at least 10 volts on pin 20 of the plug.
Let me know what you find from all the above.
The CCD wiring checkout is pretty extensive and if 66 is no longer present I doubt that would be worthwhile.
Thanks for the rating and nomination, Jay.
Jay Brodsky wrote at 2015-12-15 05:25:36
Finally got my van back from the mechanic and ordered a new [reman]PCM from my parts house online, per my VIN and the number on the old PCM. Resistance on PCM pin 11 to coil-pack pin 2 was .3/.2 on 200/))) ohm scale - figured that was tolerable. Could not get steady readings on PCM pins 10 and 50. Could not verify voltage on pin 20 as battery was already removed from car.
Finally received and installed new PCM, in spite of repeated warnings in the packing material, 'Modules rarely fail on their own. Ensure root causes are repaired before installing this module!' I must say, though, there was a fair amount of corrosion on the exterior of the old PCM, which i can't imagine was doing it any good. Engine started right up, went to town and back, running as well as it ever has.
Thanks again, Roland; you get well-deserved 10's all the way around! :)
Thanks for that report, and the good news.