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DTC codes / C06xx · Brakes, steering and suspension / C0612

C0612Right Park Brake Actuator Control Circuit High

The C0612 code indicates that the electronic brake control module has detected an abnormally high voltage on the control circuit for the right-side park brake actuator, which is the electric motor that applies the parking brake on that wheel. This high voltage condition typically means the circuit is open, shorted to power, or the actuator motor has failed, preventing proper park brake operation.

SystemChassis
Code typeGeneric (all makes)
SeverityMedium
Fix difficultyIntermediate
AreaBrakes, steering and suspension

Symptoms you may notice

  • The parking brake warning light or brake system warning light illuminates on the dashboard.
  • The right rear parking brake may fail to apply or release, causing a dragging brake or a vehicle that rolls when parked.
  • A chime or message may appear indicating a parking brake fault or service brake system.
  • The electronic parking brake switch may feel unresponsive or require multiple presses to engage or disengage.
  • Often no symptoms besides the warning light, especially if the fault is intermittent or only affects one side.

Common causes, most likely first

  1. An open circuit in the right park brake actuator control circuit, such as a broken wire or disconnected connector.
  2. A short to voltage on the control circuit, often caused by chafed wiring contacting a power source.
  3. A failed right park brake actuator motor, which can draw excessive current or show an open winding.
  4. Corroded or damaged electrical connectors at the actuator or control module, leading to high resistance.
  5. A faulty electronic brake control module, though this is less common and should be diagnosed last.
  6. Water intrusion or road debris damaging the actuator or its wiring harness.

How to diagnose and fix it

  1. Inspect the right park brake actuator and its wiring for visible damage, corrosion, or loose connectors, and repair as needed.
  2. Disconnect the actuator connector and measure resistance across the motor terminals to check for an open winding or short.
  3. Check for voltage on the control circuit with the park brake commanded on and off, comparing to the left side for reference.
  4. Perform a wiggle test on the harness while monitoring voltage or resistance to identify intermittent faults.
  5. If the circuit and actuator test good, check for technical service bulletins or software updates for the electronic brake control module.
  6. Replace the right park brake actuator if it fails electrical testing, then clear codes and verify proper operation.
  7. If all else fails, diagnose the electronic brake control module for internal faults, but only after ruling out all external circuits.

What a high voltage code really means

  • A high voltage code on an actuator control circuit often indicates an open circuit rather than a short to power, because the module sees a lack of load as a high voltage on the driver output.
  • The right park brake actuator is sometimes shared with the left actuator through a common power or ground, so a fault on one side can affect the other if the shared circuit fails.
  • Intermittent C0612 codes are frequently caused by a chafed wire near the actuator where it flexes with suspension movement, which may only show up during a wiggle test.
  • Replacing the actuator without checking the connector pins for corrosion or spread terminals can lead to a repeat failure, as the high resistance may be in the connector, not the motor.
  • Some vehicles require a calibration or initialization procedure after actuator replacement, and skipping this step can set a new code or leave the park brake inoperative.

Can I keep driving with C0612?

If the parking brake warning light is on and the right park brake does not apply, the vehicle may roll when parked on a slope, so use wheel chocks or park on level ground until repaired. Avoid using the electronic parking brake repeatedly, as a dragging brake could overheat and cause further damage.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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