C0568: Brake Booster Solenoid Circuit High

What it means

The brake booster solenoid circuit voltage is above 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 electrically controls a brake-assist function. This code sets when its voltage rises above the expected range, commonly because the control wire is shorted to battery voltage or pinched against a live supply.

Common causes

Most likely first.

1. Wiring shorted to battery
2. Connector pins corroded - high contact resistance
3. Supply wire pinched against B+ source

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 establish when the solenoid circuit voltage went high and whether the solenoid was commanded.
2. Inspect the solenoid connector and nearby harness for pinched insulation, melted areas, or contact with a battery-positive feed.
3. Check connector terminals for corrosion, displaced pins, or evidence of bridging between circuit contacts.
4. Using the wiring diagram, test the control wire for a short to battery voltage with the circuit isolated as specified by the manufacturer.
5. If the harness is clear, test the solenoid and module output circuit against the manufacturer's specification.

Common fixes

• Repair wiring pinched against a battery-positive source.
• Replace damaged connector terminals or a connector that allows circuit bridging.
• Repair a shorted control wire in the harness.
• Replace the solenoid or repair the module only if testing confirms that component is responsible.

Can I keep driving?

Brake assist may be reduced or behave unpredictably, so avoid unnecessary driving and leave extra stopping distance. If braking response changes, stop safely and arrange inspection before continuing.