Diagnosis instructions for the trailer module

The trailer module (AHM) detects and reacts to the following faults:

• Checksum error of the various memories and watchdog reset
• Faults of the CAN drivers
• Line faults of the CAN interface and of the brake light input
• Line fault of all outputs with short circuit and wire break
• Undervoltage or overvoltage and implausibility of the voltage at the trailer module (AHM) compared to the vehicle voltage
• Implausibility of a CAN message "Braking" compared to the hard-wired brake light input at the control unit
• Implausibility of the sense values of the lighting outputs of the control unit
• Faults at the lamp outputs of the trailer module (AHM) are output as Check Control messages

Notes on encoding/programming 

After installation of a trailer module (AHM), the control unit must be re-encoded. In doing so, observe the various national versions.

We can assume no liability for printing errors or inaccuracies in this information and reserve the right to introduce technical modifications at any time.