Engine-Codes - GMC - C1277 GMC

C1277 GMC Code - Requested Torque Signal Circuit Malfunction

- Code Popularity: 5,477 Views
- Repair Importance Level: 3/3
- Repair Difficulty Level: 3/3
Table of contents
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What are the Possible Causes of the DTC C1277 GMC?

NOTE: The causes shown may not be a complete list of all potential problems, and it is possible that there may be other causes.
  • Faulty Electronic Brake Control Module (EBCM)
  • Faulty Powertrain Control Module (PCM)
  • EBCM harness is open or shorted
  • EBCM circuit poor electrical connection
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How to Fix the DTC C1277 GMC?

Check the 'Possible Causes' listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.

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What is the Cost to Diagnose the Code?

Labor: 1.0

The cost to diagnose the C1277 GMC code is 1.0 hour of labor. The diagnosis time and labor rates at auto repair shops vary depending on the location, make and model of the vehicle, and even the engine type. Most auto repair shops charge between $75 and $150 per hour.

When is the Code Detected?

The Powertrain Control Module (PCM) does not receive the desired pulse width signal from the Electronic Brake Control Module (EBCM)

What are Code Possible Symptoms?

  • Anti-Lock Brake System (ABS) Warning Light ON
  • Engine Light ON (or Service Engine Soon Warning Light)

What Does the C1277 GMC Code Mean?

The Electronic Brake Control Module (EBCM) and the Powertrain Control Module (PCM) simultaneously control the traction control. The EBCM sends a Requested Torque message via a pulse width modulated (PWM) signal to the PCM. The duty cycle of the signal is used to determine how much engine torque the EBCM is requesting the PCM to deliver. Normal values are between 10 and 90 percent duty cycle. The signal should be at 90 percent when traction control is not active and at lower values during traction control activations. The PCM supplies the pull up voltage that the EBCM switches to ground to create the signal.

C1277 GMC Code - Requested Torque Signal Circuit Malfunction

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