B1299 – Power Supply Sensor Circuit Short To Ground

The ODBII code B1299 indicates a short circuit to ground in the power supply sensor circuit, which typically affects the operation of various vehicle systems that rely on this sensor for proper functioning.

The severity of ODBII code B1299 is typically considered moderate to severe.

Common Causes For: B1298 Power Supply Sensor Circuit Short To Battery

• Damaged wiring or connectors
• Shorted sensor circuit
• Faulty power supply sensor
• Grounding issues
• Corroded connections
• Faulty ECM (Engine Control Module)

Common misdiagnosis for B1299 Power Supply Sensor Circuit Short To Ground

• Faulty power supply sensor
• Wiring issues or shorts in the harness
• Faulty engine control module (ECM)
• Bad ground connections
• Issues with the battery or charging system
• Faulty connectors or terminals
• Incorrectly installed aftermarket accessories
• Malfunctioning body control module (BCM)

Common Troubleshooting Steps

The OBD-II code B1299 indicates a problem with the power supply sensor circuit, specifically a short to ground. This code is often related to issues in the vehicle’s electrical system, particularly in the power supply circuit for various sensors. Here are some common troubleshooting steps to diagnose and resolve the issue:

• Check for Other Codes: Use an OBD-II scanner to check for any additional trouble codes. This can provide more context and help identify related issues.
• Inspect Wiring and Connectors: Visually inspect the wiring harness and connectors associated with the power supply sensor circuit. Look for signs of damage, fraying, corrosion, or loose connections.
• Pay special attention to areas where the wiring may be exposed to heat, moisture, or physical wear.
• Test the Power Supply Sensor: If applicable, test the power supply sensor itself for proper operation. This may involve checking its resistance or voltage output according to the manufacturer’s specifications.
• Check for Short Circuits: Use a multimeter to check for continuity in the power supply circuit. Disconnect the battery and test for continuity between the power supply wire and ground. A reading of zero ohms indicates a short to ground.
• Inspect the circuit for any pinched or damaged wires that could be causing a short.
• Inspect Ground Connections: Ensure that all ground connections related to the power supply sensor circuit are clean, tight, and free of corrosion. Poor ground connections can lead to erroneous readings and codes.
• Check Fuses: Inspect the relevant fuses in the fuse box. A blown fuse may indicate an overload or short circuit in the system.
• Test Voltage Supply: With the ignition on (but the engine off), use a multimeter to check the voltage at the power supply sensor. Ensure it is receiving the correct voltage as specified in the service manual.
• Look for Environmental Factors: Consider whether any recent repairs, modifications, or environmental factors (like water intrusion) could have affected the wiring or sensors.
• Clear Codes and Test Drive: After performing repairs or adjustments, clear the trouble codes using the OBD-II scanner and take the vehicle for a test drive to see if the code returns.
• Consult Service Manual: If the issue persists, consult the vehicle’s service manual for specific diagnostic procedures and specifications related to the power supply sensor circuit.1
• Seek Professional Help: If you are unable to diagnose or resolve the issue, consider seeking assistance from a qualified mechanic or automotive technician who has experience with OBD-II systems. By following these steps, you should be able to identify and address the cause of the B1299 code effectively.