2006 Chevrolet 2500HD 6.0L Engine P0327 and P0331 Knock Sensor Fault: No Voltage from PCM?
I've reviewed several previous threads on P0327 and P0331 codes, and I'm experiencing the same issue with my 2006 Chevrolet 2500HD 6.0L diesel engine. Initially, I received a P0331 code, which was traced to a rusted rear knock sensor. After replacing both knock sensors and the associated wiring harness, the problem persisted — now I'm seeing both P0327 and P0331 codes. I performed continuity testing on the sensor wires and found resistance values of 99 ohms and 101 ohms, which are below General Motors' specified limits. However, a critical issue I've identified is that there is no voltage detected at the Powertrain Control Module (PCM) pins 51 and 11 — the reference points for knock sensor operation. According to OEM specifications, when the key is in the 'run' position with wires connected, the KOEO (Key-On-Engine-Off) voltage should be approximately 2.5 volts; when disconnected, it should read around 5 volts. The absence of this voltage suggests a potential failure in the PCM or its power supply circuit. I'm now wondering whether I need to replace the PCM entirely, or if there's another underlying cause — such as wiring issues upstream or a faulty ground connection — that I might be overlooking. Any insights from others who've faced this would be greatly appreciated before making an expensive part replacement.
I know it shouldn't have been washed, but I have a 2006 Chevrolet 2500HD 6.0L engine with P0327 and P0331 codes. A simple fix? Not this time. I replaced both knock sensors and the harness, but the codes persist. The wiring resistance is below GM specs, yet there's no reference voltage from the PCM — specifically on pins 51 and 11. According to specifications, KOEO voltage should be around 2.5 volts with wires connected and 5 volts when disconnected. I'm now considering a PCM replacement — am I missing something or is this a definitive failure?