B1338 – Door Ajar RR Circuit Short To Ground

The ODBII code B1338 indicates a fault in the rear right door ajar circuit, specifically a short to ground condition, meaning there is an unintended connection to the ground in the circuit that detects whether the rear right door is closed or open.

The severity of ODBII code B1338 Door Ajar RR Circuit Short To Ground is moderate.

Common Causes For: B1337 Door Ajar RR Circuit Short To Battery

• Damaged wiring or connectors in the door ajar circuit.
• Faulty door ajar switch.
• Short circuit in the wiring harness.
• Corrosion or poor connections at the door switch or connector.
• Malfunctioning body control module (BCM).

Common misdiagnosis for B1338 Door Ajar RR Circuit Short To Ground

• Faulty door switch
• Wiring issues
• Body control module (BCM) failure
• Shorted wiring harness
• Malfunctioning door latch assembly
• Incorrectly installed or damaged door seal
• Faulty BCM programming or configuration
• Issues with other door sensors or switches

Common Troubleshooting Steps

When dealing with an OBD-II code B1338, which indicates a “Door Ajar RR Circuit Short To Ground,” it typically points to an issue with the rear right door’s ajar switch or its associated wiring. Here are some common troubleshooting steps to help diagnose and resolve the issue:

• Visual Inspection: **Check Wiring and Connectors: Inspect the wiring harness and connectors leading to the rear right door ajar switch for any signs of damage, fraying, or corrosion.
• **Look for Shorts: Check for any exposed wires that may be touching the vehicle’s chassis or other components, which could cause a short to ground.
• Test the Door Ajar Switch: **Functionality Check: Manually operate the door ajar switch (usually located in the door latch mechanism) to see if it is functioning correctly. You can do this by opening and closing the door and observing if the interior lights or dashboard indicators respond appropriately.
• **Continuity Test: Use a multimeter to check for continuity in the switch. If the switch is stuck in the “on” position, it may need to be replaced.
• Check for Ground Issues: **Ground Connections: Ensure that the ground connections for the door ajar circuit are secure and free of corrosion. A poor ground can lead to false readings.
• **Test Grounding: Use a multimeter to check the ground circuit for continuity and proper voltage.
• Inspect the Body Control Module (BCM): **BCM Functionality: The BCM often controls the door ajar signals. Check for any fault codes related to the BCM and ensure it is functioning correctly.
• **Reprogram or Reset: If the BCM is suspected to be faulty, it may need to be reprogrammed or reset.
• Scan for Additional Codes: **Check for Other Codes: Use an OBD-II scanner to check for any additional trouble codes that may provide more context or indicate related issues.
• Test the Circuit: **Voltage Test: With the door open and closed, use a multimeter to test the voltage at the door ajar switch connector. Compare the readings to the specifications in the vehicle’s service manual.
• **Wiring Diagram: Refer to the vehicle’s wiring diagram to trace the circuit and identify any potential issues along the path.
• Replace Faulty Components: If any components (wiring, connectors, or the door ajar switch) are found to be faulty during testing, replace them as necessary.
• Clear Codes and Test Drive: After repairs, clear the trouble codes using an OBD-II scanner and take the vehicle for a test drive to see if the code returns.
• Consult a Professional: If the issue persists after performing these steps, it may be beneficial to consult a professional mechanic or technician for further diagnosis. By following these troubleshooting steps, you should be able to identify and resolve the issue related to the B1338 code.