Conditions for diagnostic trouble code (DTC):
1) Current below normal or open circuit

Diagnostic operating conditions
1) Ignition key in ON position

Observable symptoms
1) Reduced engine braking since the compression brake cannot be activated
2) Reduced gear selection performance for some automatic transmissions

Probable cause
1) Open circuit on common supply wire or open circuit on fuse FE9
2) Open circuit in the compression brake solenoid valve
3) Open circuit between Engine control module (ECM) and Solenoid valve, compression brake