Communication with the retarder
â–¶ How to fix
Check the red CAN bus wiring and connectors. Also check whether the GMS control unit or coordinator has generated any fault codes. Also check the instrument cluster configuration.
What you'll see
No driver-visible symptom recorded.
System reaction
No system-reaction text recorded.
Diagnostic depth
Detection
Communication between the instrument cluster and retarder, which is controlled by the GMS control unit, has been interrupted.
Possible cause
Short circuit or open circuit in the red CAN bus. There may also be an internal fault in the GMS control unit.