C0567: Brake Booster Solenoid Circuit Low

What it means

The brake booster solenoid circuit voltage is below the expected range. The brake booster system may not operate as intended.

At a glance

• Usually lights the ABS or stability-control warning light
• The engine or gearbox may go into limp mode

How it works

The brake booster solenoid circuit carries the electrical control for a brake-assist function. This code sets when the circuit voltage is below its expected range, which can happen if the control wire is grounded or a connection has excessive resistance.

Common causes

Most likely first.

1. Wiring shorted to ground
2. Connector pins corroded - high contact resistance
3. Harness chafing through insulation

Symptoms

• Brake or ABS warning light
• Brake assist may be reduced, depending on the system

How to diagnose it

1. Read brake-module freeze-frame and live data to confirm when the solenoid circuit voltage fell and whether brake-assist commands were affected.
2. Inspect the solenoid connector for corrosion, moisture, loose terminals, or poor pin contact.
3. Check the harness for chafing or crushed insulation that could let the control wire contact ground.
4. Use the wiring diagram to test the solenoid circuit for a short to ground and check connector voltage and continuity.
5. If wiring and connections pass, test the solenoid and module output against the manufacturer's specification.

Common fixes

• Clean and secure corroded or loose solenoid connector terminals.
• Repair chafed wiring that is contacting ground.
• Replace a solenoid that fails its electrical test.
• Repair the module output circuit only if testing isolates the fault to the module.

Can I keep driving?

Brake assist may be reduced, which can make the pedal harder to press or increase stopping distance. Limit driving and avoid situations that require sudden braking; stop if braking feel changes significantly.