P0606 — PCM Processor Fault
High severityWhat it means
P0606 is stored when the engine control unit sees a fault involving the powertrain control module (PCM) processor. This code means the PCM detected an internal processor fault — the computer that runs the engine flagged a problem with itself. The fault points to the module's internal operation or its power, ground and network connections rather than a single external sensor.
Common symptoms
- Multiple warning lights or limp mode
- Stalling or no-start
- Erratic engine behaviour
Likely causes
- Low voltage, poor ground or a corroded connector at the module
- Low voltage or a poor ground to the PCM
- Internal PCM/processor failure
What to check first
- Verify module power, grounds and battery voltage before suspecting the module itself
- Check PCM power, grounds and battery voltage
- Confirm the latest software and rule out wiring before replacement
Can you keep driving?
Treat it as serious — internal PCM faults can stall the engine or limit power; diagnose before driving far.
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