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DTC codes / C05xx · Brakes, steering and suspension / C0568

C0568Brake Booster Solenoid Circuit High

C0568 indicates that the brake booster solenoid circuit is showing a high voltage condition, meaning the control module has detected an abnormally high voltage on the solenoid's control circuit, often due to a short to power or an open circuit. The computer expects a certain voltage range when the solenoid is commanded, and a reading above that threshold sets this code.

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

Symptoms you may notice

  • Illumination of the brake system warning light or ABS light on the dashboard
  • Often no symptoms besides the warning light, with normal brake pedal feel
  • Reduced or inconsistent brake assist, requiring more pedal effort
  • A clicking or buzzing noise from the brake booster area when the brake pedal is pressed
  • The cruise control may become inoperative or disengage unexpectedly
  • In some cases, the vehicle may enter a limp mode affecting brake-related functions

Common causes, most likely first

  1. A short to voltage in the brake booster solenoid control circuit wiring
  2. An open circuit in the solenoid ground or power feed, causing the module to see high voltage
  3. A faulty brake booster solenoid itself, with an internal open or high resistance
  4. Corroded or damaged electrical connectors at the solenoid or control module
  5. A failed brake control module or ABS module, misinterpreting the circuit voltage
  6. Aftermarket accessories or wiring repairs that inadvertently tap into the solenoid circuit

How to diagnose and fix it

  1. Verify the code with a scan tool and check for any related codes in the brake control module
  2. Inspect the brake booster solenoid connector and wiring for corrosion, damage, or loose pins
  3. Measure resistance across the solenoid terminals and compare to the manufacturer's specification
  4. Check for short to voltage on the control circuit by backprobing the solenoid connector with the key on
  5. Test the ground circuit for the solenoid to ensure it is clean and tight
  6. If the circuit tests good, substitute a known-good solenoid or module to isolate the fault
  7. Repair or replace the faulty wiring, connector, solenoid, or module as needed, then clear codes and verify

What a high voltage code really means

  • A high voltage code often results from an open circuit rather than a short to power, because the module pulls the circuit high when it cannot find a ground path.
  • The brake booster solenoid is sometimes part of the ABS pump assembly, so a failed solenoid can require replacing the entire assembly rather than a separate part.
  • A weak or failing battery or charging system can cause erratic voltage readings that set this code, so always check battery health first.
  • This code can be set by a faulty brake pedal position sensor or cruise control switch that shares the same reference voltage circuit.
  • After replacing a solenoid or module, some vehicles require a calibration or learn procedure to clear the code permanently.

Can I keep driving with C0568?

If the brake pedal feels normal and the only symptom is a warning light, you can drive cautiously to a repair shop, but avoid heavy braking or towing. If you notice reduced brake assist or any change in pedal feel, stop driving and have the vehicle towed to prevent a safety risk.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

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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