What does it mean?
C1506 is a Chassis (ABS, traction control, steering) fault code. It indicates: Left Front Tire Pressure Trigger Module Performance .
Symptoms
- Tyre pressure warning lamp on with a system fault rather than a low pressure warning
- The left front position cannot be located or learned during a relearn
- Pressure values missing for that wheel or swapped with another position
- Relearn procedure stops part way through and times out
- Tyres themselves are correctly inflated and the vehicle drives normally
Likely causes
- Failed trigger module in the left front wheel arch
- Water intrusion and corrosion at the trigger module connector, which sits in a wet, dirty area
- Open, shorted or chafed wiring between the trigger module and the receiver
- Poor ground for the trigger circuit
- Trigger module loose, hanging or moved away from the wheel after liner or suspension work
- Weak or dead sensor in the left front wheel that will not answer the trigger
- Faulty tyre pressure receiver module
How to fix it
- Start a wheel position relearn and note exactly where it stops
- Trigger the left front sensor directly with a TPMS tool to confirm the sensor still transmits
- Remove the wheel arch liner and inspect the trigger module and its connector for water and corrosion
- Check power, ground and signal at the trigger module connector
- Test the harness back to the receiver for open circuits and shorts
- Look for aftermarket electronics that could interfere with the low frequency trigger
- Replace the trigger module, repeat the relearn and confirm every position reads correctly