C1277: OBD-II code C1277 flags a fault in the requested-torque signal from the EBCM to the PCM — traction control cannot ask the engine to cut power during wheel slip.

Symptoms

• ABS and traction control warning lamps illuminate; the code often appears alongside PCM communication codes.
• Traction control cannot reduce engine torque during wheel-spin events, so slippery-surface acceleration feels less controlled.
• Normal driving is unaffected; only traction-control effectiveness is reduced.

Common causes

• A serial data communication fault (CAN or Class 2) between the EBCM and the PCM, preventing torque-request messages.
• An EBCM fault that fails to broadcast a valid torque-request message on the bus during traction events.
• Damaged bus wiring, a bad splice, or another failed module on the bus disrupting the shared communication network.

What to do?

Scan every module for related U-codes — they usually pinpoint the bus fault. Check the serial data bus for correct resistance and no shorts. Confirm the EBCM broadcasts torque requests during a simulated TCS event. Repair bus wiring or replace the failed module, then clear the code.