The P0651 trouble code indicates an issue with the sensor reference voltage “B” circuit being open. This circuit provides reference voltage to various sensors throughout the vehicle, allowing them to function properly. When the ECM or PCM detects an open circuit in the sensor reference voltage “B” circuit, it will trigger this trouble code.
P0651 Sensor Reference Voltage “B” Circuit Open
Code symptoms P0651.
1. Check engine light (MIL) may illuminate.
2. Engine performance issues, such as hesitation or stalling.
3. Other related trouble codes may be present.
This code is common in brands such as:: Chevrolet, Renault, Ford, Toyota, Nissan, Mercedes Benz, Honda.
Causes of the code P0651.
1. Faulty sensor reference voltage “B” circuit.
2. Open or short circuit in the sensor reference voltage “B” circuit.
3. Corrosion or damage to wiring or connectors in the circuit.
4. Faulty ECM or PCM.
Code Solutions P0651.
1. Inspect the wiring and connectors in the sensor reference voltage “B” circuit for any signs of damage, corrosion, or loose connections. Repair or replace damaged components as necessary.
2. Clear the trouble codes and perform a test drive to verify if the issue persists. If the code returns, further diagnosis may be required.
3. Check the voltage output of the ECM or PCM to ensure it is within specifications. If not, the ECM or PCM may need to be replaced.
4. Follow manufacturer-specific diagnostic procedures outlined in the vehicle’s service manual to accurately diagnose and repair issues related to the sensor reference voltage “B” circuit. If needed, seek assistance from a qualified technician or dealership.