P0651
PowertrainPcm Referencemoderate severitySensor Reference Voltage B Circuit
What P0651 Means
The PCM detected a fault in the B sensor reference voltage circuit. Multiple sensors sharing this reference may report inaccurate values.
Symptoms
- Multiple sensor codes
- Erratic engine performance
- Check engine light on
Common Causes
- Short in reference voltage circuit
- Damaged wiring or connector
- Faulty sensor loading the circuit
- PCM internal fault
Diagnostic Steps
- Read all stored codes
- Inspect reference circuit wiring
- Measure reference voltage at sensors
- Isolate faulty sensor or PCM
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