P0643
PowertrainPcm Referencemoderate severitySensor Reference Voltage A Circuit High
What P0643 Means
The PCM detected the sensor reference voltage on circuit A is above normal. This can cause incorrect readings from affected sensors.
Symptoms
- Multiple sensor codes
- Check engine light on
- Erratic performance
Common Causes
- Short to voltage on reference circuit
- Damaged wiring
- Corroded connector
- Faulty PCM
Diagnostic Steps
- Measure reference voltage at sensors
- Inspect wiring for short to power
- Isolate affected circuit
- Repair wiring or replace PCM
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