P0605
PowertrainPcm Internalhigh severityInternal Control Module Read Only Memory (ROM) Error
What P0605 Means
The PCM detected a fault in its Read Only Memory, where the program calibration is stored. This usually indicates corrupt software or an internal module failure.
Symptoms
- Check engine light on
- Engine may not start
- Erratic engine operation
Common Causes
- Corrupt or failed PCM ROM
- Internal module hardware failure
- Failed software update
- Voltage supply issues
Diagnostic Steps
- Verify battery voltage and grounds
- Check PCM power supply circuits
- Attempt PCM reflash with correct calibration
- Replace PCM if reprogramming fails
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