C0567 indicates that the control module has detected a lower-than-expected voltage in the brake booster solenoid circuit. This typically means the circuit is shorted to ground, the solenoid has failed internally, or there is significant voltage drop between the module and the solenoid. When this occurs, the system may be unable to regulate vacuum assist properly, which can reduce braking performance.
The solenoid windings can develop an internal short or incorrect resistance, causing the control voltage to drop below the module’s threshold and preventing proper vacuum regulation.
Damaged or chafed insulation can allow the circuit wire to contact the vehicle frame or another ground path, pulling the detected voltage low.
Poor terminal contact or moisture intrusion at the solenoid or pump connector can introduce unwanted resistance that affects circuit voltage.
On designs where the solenoid is built into the electric vacuum pump, failure of the assembly can set this code even when the brake booster itself is mechanically sound.
Although uncommon, an internal issue with the module’s output driver can incorrectly set a low-voltage code; this should only be considered after the solenoid and entire harness are proven good.
You can usually drive to a repair facility, but expect increased brake pedal effort and longer stopping distances because vacuum assist may be reduced or absent.
Usually not. The code points to a solenoid circuit fault, and the solenoid or vacuum pump is often a separate component from the booster itself.
No. Control module failure is an uncommon root cause for this code. Most instances are resolved by repairing the solenoid, wiring, or connector. Replacing the module before verifying the circuit and component is usually a mistake.
A shorted or inoperative solenoid can prevent the system from reaching or holding the target vacuum, causing the pump to run continuously or not run when needed.