The B1338 OBD2 fault code relates to the Door Ajar RR circuit. This controls central locking functionality. When the circuit circuit failure, door locks may not operate properly.

At AIscanAuto, we help drivers quickly identify OBD2 trouble codes, understand their root causes, and find the right fix.

Symptoms

• Door locks not working with remote or switches
• One or more doors not locking/unlocking
• Security system issues

Common Causes

• Failed actuator — worn motor
• a general circuit failure is detected — can result from wiring faults, connector issues, or component failure
• Wiring issues — damaged door harness
• Connector problems — corrosion

Step-by-Step Diagnosis

1. Scan with OBD2 tool — Confirm B1338.
2. Test locks — Check all doors.
3. Inspect wiring — Check door harnesses.
4. Test actuator — Listen for movement.

Repair & Solutions

• Replace actuator if faulty.
• Repair wiring.
• Clean connectors.

Related Codes

• B1335 — Door Ajar RR Circuit Failure
• B1336 — Door Ajar RR Circuit Open
• B1337 — Door Ajar RR Circuit Short To Battery

External References

- OBD2Pros — Complete DTC Reference

About This Guide

This diagnostic article is an original guide created by AIscanAuto for educational and troubleshooting purposes. The technical information about OBD2 DTC codes is based on publicly available automotive diagnostic standards and industry best practices. External links provided in the "External References" section are for additional reading and context only — they do not imply endorsement or ownership of third-party content. All repair procedures should be performed by qualified technicians.