Chrysler Repair/'96 3.8L: no start: codes for MAP and TPS sensors
Kevin declined this question while you were on vacation [i trust you enjoyed it]... hoping you can help:
Same '96 Dodge Grand Caravan LE 3.8L i replaced PCM in, last December. Car ran fine for 3 months, then died on road. Seemed like a fuel problem, i replaced fuel pump. Engine turned over fine, tried to catch, but would not run. Helper assured me there was air in fuel line, so after much persistence i got it to catch... catch and chug [400 RPM] for 5 seconds and die... catch, run longer, die... eventually it smoothed out at 800 RPM idle, revved smoothly. I drove around block 3 times, turned engine off, and restarted it fine. A few hours later, car would not start again. Same procedure for twenty minutes, then, under a static load test at about 3000 RPM, engine suddenly died. No spark, no spark with test plug on #6 wire. Fuel pump runs; Schrader valve shows fuel in fuel rail. No OBD key codes [except expected 12-55]. All other electricals seem to be ok [fuses, relays, lights, etc. New coil-pack (replaced before ECM) showed internal heat damage so i reinstalled old coil-pack - no change] I was so happy new PCM solved problem last Fall - could it have operated fine for 3 months and then suddenly die? Suggestions?
FOLLOW UP: I contacted parts house who allowed the PCM was still under warranty and offered to replace it. I installed replacement PCM, and the starter wouldn't even turn over, but i did get key codes: 35-24-61, confirmed by plug-in OBD II analyzer: p0106 and p0122 [MAP and TPS sensors low voltage...] I notice you often recommend EGR valve rehab, as this can affect other sensors and engine performance, but shut down engine completely [possibly by way of ASD relay]? And i can't find such a device on my car, haven't been able to perform wiring diagnostics on other sensors, and have been at a loss for how to proceed. Out of frustration, i reinstalled the older PCM. Starter now turns, with conditions as described in original question, no codes, etc...
I read your 10/2/2015 answer to 'John; 97 Concorde, 3.5l; no start' with great interest - could any of that information apply to me?
My initial suggestion would be to check pin 61 at the PCM to see if you are getting 5 volts on the violet/white wire when the key is in he run position. That same wire goes to the TPS and MAP sensors which show the code you got as being low voltage so maybe either there is short in the wire or the 5V supply circuit in the PCM is faulty. Those are the only parts of the circuitry that use that supply voltage so it is likely involved here. See if disconnecting the plugs at those two sensors changes the voltage showing on the violet/white wire. None of the codes point toward the spark circuit so we'll deal with that later. I have to make and eat dinner at this point so let me know what you find about the 5v supply situation.4