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DTC codes / C05xx · Brakes, steering and suspension / C05D7

C05D7Brake Transmission Shift Interlock (BTSI) Control Circuit

The C05D7 code indicates that the vehicle's computer has detected a fault in the electrical circuit that controls the Brake Transmission Shift Interlock (BTSI) system, which prevents the shifter from moving out of Park unless the brake pedal is pressed. The computer monitors the circuit for abnormal voltage or current and sets this code when the signal does not match expected values, often due to a wiring issue, a faulty solenoid, or a failed brake pedal position sensor.

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

Symptoms you may notice

  • The gear shifter cannot be moved out of Park even with the brake pedal pressed.
  • The brake pedal must be pressed multiple times or with extra force to release the shifter.
  • A warning light on the dashboard, often the brake or transmission indicator, may illuminate.
  • The shifter may feel loose or move without pressing the brake, indicating a stuck interlock.
  • In some cases, the vehicle may not start because the interlock system is tied to the ignition circuit.
  • Often no symptoms besides the warning light, especially if the fault is intermittent.

Common causes, most likely first

  1. Faulty brake pedal position sensor (brake light switch) not sending the correct signal to the BTSI control module.
  2. Damaged or corroded wiring in the BTSI control circuit, including open or short circuits.
  3. Failed BTSI solenoid or actuator that physically locks the shifter.
  4. Blown fuse or poor ground connection supplying power to the BTSI system.
  5. Malfunctioning body control module (BCM) or transmission control module (TCM) that controls the interlock.
  6. Aftermarket accessories or improper wiring repairs interfering with the circuit.

How to diagnose and fix it

  1. Verify the battery voltage and check all fuses related to the BTSI system, including the brake light fuse.
  2. Inspect the brake pedal position sensor and its wiring for damage or corrosion, and test its operation with a multimeter.
  3. Check the BTSI solenoid for resistance and function, and test for power and ground at the solenoid connector.
  4. Perform a wiggle test on the wiring harness while monitoring the circuit with a scan tool to identify intermittent faults.
  5. Check for technical service bulletins (TSBs) or software updates for the BCM or TCM that may address known BTSI issues.
  6. If all electrical checks pass, diagnose the BCM or TCM for internal faults using a factory-level scan tool.
  7. Repair or replace the faulty component, clear the code, and verify the shifter operates correctly with the brake pedal.

Common BTSI circuit misdiagnosis traps

  • A worn brake pedal position sensor often causes this code without setting a brake light code, so technicians who only check for brake light operation may miss it.
  • The BTSI solenoid can fail mechanically while still showing correct electrical resistance, so a resistance check alone is not conclusive.
  • Corrosion inside the shifter assembly connector is a frequent hidden cause, especially in vehicles with spills or high humidity exposure.
  • Aftermarket remote starters or alarm systems tapped into the brake or shifter wiring can back-feed the BTSI circuit and set this code.
  • The code can be set by a low battery or charging system issue that causes voltage spikes, so always verify battery health before replacing parts.

Can I keep driving with C05D7?

If the shifter cannot be moved out of Park, the vehicle is undrivable and should not be forced. If the code is stored but the shifter works normally, you may drive cautiously to a repair shop, but avoid relying on the interlock and be prepared for the shifter to lock unexpectedly.

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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