The P0699 trouble code indicates that the Engine Control Module (ECM) or Powertrain Control Module (PCM) has detected a high voltage condition in the sensor reference voltage “C” circuit. Sensor reference voltage “C” is a specific voltage signal used by various sensors in the vehicle’s engine management system to provide crucial data to the ECM or PCM for engine operation. When the ECM or PCM detects a high voltage condition in this circuit, it triggers the P0699 code.
Sensor Reference Voltage “C” Circuit High
Code symptoms P0699.
1. Check Engine Light (CEL) illuminated on the dashboard.
2. Engine may run in a reduced power or “limp” mode to prevent potential damage.
3. Decreased fuel efficiency.
4. Engine hesitation or stalling.
5. Vehicle may fail to start or have difficulty starting.
This code is common in brands such as:: Chevrolet, Renault, Ford, Toyota, Nissan, Mercedes Benz, Honda.
Causes of the code P0699.
1. High voltage condition in the sensor reference voltage “C” circuit due to a faulty sensor or electrical component.
2. Wiring or connector damage or corrosion in the sensor reference voltage “C” circuit.
3. Faulty ECM or PCM (rare).
Code Solutions P0699.
1. Use a diagnostic scanner to retrieve freeze frame data and all associated trouble codes. This information can help pinpoint the root cause of the issue.
2. Check the voltage in the sensor reference voltage “C” circuit using a digital multimeter. Ensure the voltage is within the manufacturer’s specified range. If it’s too high, proceed with further diagnosis.
3. Inspect the wiring harness and connectors in the sensor reference voltage “C” circuit for any signs of damage, corrosion, or loose connections. Repair or replace damaged components as needed.
4. Test the sensor requiring sensor reference voltage “C” for proper operation. Test the sensor according to manufacturer-specific procedures outlined in the vehicle’s service manual. Replace the sensor if it is faulty.
5. If the wiring, connectors, and sensors are in good condition but the code persists, it may indicate a fault in the ECM or PCM. In this case, the ECM or PCM may need to be replaced or reprogrammed by a qualified technician.
6. After any repairs are made, clear the trouble codes and perform a test drive to verify that the issue has been resolved. If the code returns, further diagnosis may be necessary to identify the underlying problem.
7. Follow manufacturer-specific diagnostic procedures outlined in the vehicle’s service manual to accurately diagnose and repair issues related to the sensor reference voltage “C” circuit. If needed, seek assistance from a qualified technician or dealership.