DTC B1056 Hummer
Relay Control Module Lost Communication with MICU (ALARM Message)
Relay Control Module Lost Communication with MICU (ALARM Message)
Description
Poor communication between the Relay Control Module and the MICU If DTCs B1055, B1056, B1057, B1157, B1159, B1180, B1255, B1955, B2155, B2156, and B2161 are indicated, perform the MICU input test.
Cause and Solution
Loose or poor connections between the Relay Control Module and the MICU
Blown fuse in the main under-hood fuse box
Blown fuse in the under-dash fuse relay box
Open or Short to ground at the Relay Control Module
Open or Short to ground at drivers MICU
Faulty Relay Control Module
Faulty MICU
Video Guide
Diagnostic Info
- DTC Code: B1056
- Brand: Hummer