What does it mean?
C1277 is a Chassis (ABS, traction control, steering) fault code. It indicates: Requested Torque Signal Circuit Malfunction .
Symptoms
- Traction and stability lamps on with the systems inhibited
- No torque reduction when a driven wheel spins on a slippery surface
- Engine warning lamp may also be on, with throttle-related codes
- Throttle response may feel different or the engine may go into a reduced power mode
- Cruise control disabled
Likely causes
- Torque reduction request sent by the traction control module not acknowledged or not received by the engine module
- CAN bus fault or high resistance interrupting the request path between the two modules
- Engine control module fault that prevents it from acting on the request
- Throttle body or accelerator pedal sensor fault so requested and actual torque never agree
- Corroded connectors or damaged bus wiring between the modules
- Incorrect or mismatched software after a module replacement
- Internal fault in the chassis control module generating the request
How to fix it
- Read codes from every module and deal with throttle and pedal position faults first
- Compare requested torque and delivered torque in live data during a controlled traction event
- Check bus wiring, connector pins and bus resistance between the chassis and engine modules
- Inspect the throttle body and pedal sensor circuits for the faults that break the torque handshake
- Verify system voltage and grounds at both modules
- Confirm the software levels of the modules are compatible after any replacement
- Replace the chassis module last, once the bus and the engine side test good