C122B – BMW DTC

BMW DTC C122B – Left Rear Wheel Speed Sensor Circuit Electrical

DTC C122B meaning on BMW

DTC C122B on a BMW refers to a fault with the Left Rear Wheel Speed Sensor Circuit Electrical. This diagnostic trouble code indicates that there is an electrical issue with the circuit related to the left rear wheel speed sensor.

BMW DTC C122B symptoms

Symptoms of DTC C122B on a BMW may include:

• ABS warning light illuminated on the dashboard
• Traction control system malfunction
• Loss of stability control
• Erratic braking behavior

BMW DTC C122B causes

Common causes of DTC C122B on a BMW include:

• Faulty left rear wheel speed sensor
• Wiring or connector issues in the circuit
• Corrosion or damage to sensor or wiring
• ECU (Electronic Control Unit) failure

BMW DTC C122B seriousness

The seriousness of DTC C122B on a BMW lies in the potential safety implications. Issues with the wheel speed sensor circuit can affect the proper functioning of the ABS, traction control, and stability control systems, compromising the vehicle’s handling and safety.

How to diagnose DTC C122B on BMW

To diagnose DTC C122B on a BMW, you can follow these steps:

1. Use a diagnostic scanner to retrieve the fault codes from the vehicle’s ECU.
2. Inspect the left rear wheel speed sensor and its wiring for any visible damage or corrosion.
3. Test the sensor’s resistance and check for proper voltage signals.
4. Check the connectors and wiring for continuity and proper connection.
5. If necessary, perform a road test to confirm the symptoms and trigger the fault code.

How to fix DTC C122B on BMW

To fix DTC C122B on a BMW, you can try the following:

1. Replace the left rear wheel speed sensor if it is found to be faulty.
2. Repair or replace any damaged wiring or connectors in the circuit.
3. Clean any corrosion from the sensor or wiring connections.
4. If the issue persists, consider checking the ECU for faults or seeking professional help.

How to erase DTC C122B on BMW

To erase DTC C122B on a BMW, you can:

1. Use a diagnostic scanner to clear the fault codes stored in the ECU.
2. After performing the necessary repairs, reset the system by clearing the codes.
3. Ensure that the issue has been resolved before erasing the fault code.

Recommended tools & DTC Scanners for BMW

Best Diagnostic App for modern BMWs: BimmerLink

Recommended Bluetooth adapter for Bimmerlink: OBDLink CX

Cable adapter for Bimmerlink: Enet Cable USB Type C

For older BMWs we recommend: Autel AutoLink AL319 (2024 version)

Easy-to-use Multimeter for reliable diagnostics: AstroAI Auto-ranging Multimeter

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