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1997 Plymouth Grand Voyager 3.3L: Intermittent Engine Death with No Grounding on Coil Driver Wires from PCM

Model: 1997 Plymouth Grand Voyageur Fault Code: P0300 Posted: 2017-09-19 23:25

My 1997 Plymouth Grand Voyager 3.3L engine runs for 5 to 10 minutes before suddenly shutting off. After waiting one hour, the vehicle restarts and repeats the same pattern. At the coil connector, I observe momentary battery voltage when the key is turned on, followed by full battery voltage during cranking—indicating that the ASD (Accessory Shutdown) relay is being energized by the PCM. This suggests that the crankshaft and camshaft position sensors are functioning properly. However, there is no grounding detected from the PCM to the three coil driver wires. Each wire shows continuity to the terminal but no continuity to ground—indicating no short or resistance issues. The absence of grounding on the coil drivers is causing the engine to stall intermittently. Given that the vehicle runs periodically and does not exhibit consistent failure, I find it difficult to believe a faulty PCM is the root cause. I have searched extensively online but found no definitive solutions. Can anyone explain what might prevent the PCM from grounding the coil driver circuits? Is there a known sensor, wiring, or ECU-related issue specific to this 1997 Plymouth Grand Voyager model that could cause this behavior? I do not have modifications such as remote start, alarms, or added electronics—only stock setup. Thank you for any insights or troubleshooting suggestions.

Related fault codes
P0300
Comments (3)
Anonymous 2017-09-20 11:48

Use an OBD2 scanner to retrieve all stored and live diagnostic codes. The key-on/off voltage test alone is insufficient. For this vehicle, ensure it's a stock setup with no aftermarket modifications. The claim that the ASD relay is being energized due to working crank and cam sensors should be verified with actual waveform data from the CKP (crankshaft position) sensor—this may reveal inconsistencies in signal quality or timing. Additionally, check for any tachometer-related issues as they can sometimes correlate with ignition circuit faults.

Anonymous 2017-09-21 03:01

I don't have access to a scanner, but I did observe a crankshaft position (CKP) MIL code during the failure cycle. The vehicle was not modified in any way beyond factory specifications.

Anonymous 2017-09-21 07:12

Could you please specify what the exact crankshaft position (CKP) diagnostic code was and how it was resolved? Was it a current or historical code, and did it trigger any specific symptoms or repairs?