G545309p1 : Brake Vacuum Assist Function

Pinpoint tests
PINPOINT TEST G545309p1 : BRAKE VACUUM ASSIST FUNCTION
G545309t1 : CHECK THE BRAKE PEDAL TRAVEL WITH THE ENGINE OFF
1. Key off.
2. Pump the brake pedal six times and hold firm pressure on the pedal.

^ Did the pedal travel decrease and the pedal go hard as it was pumped?

-> Yes

GO to Pinpoint Test G545309t2.

-> No

CHECK the vacuum circuit to the brake booster. Start the engine and idle for three minutes, switch off then repeat the test. If the pedal travel does not decrease, suspect the brake booster.

G545309t2: CHECK THE BRAKE PEDAL TRAVEL WITH THE ENGINE RUNNING
1. With firm pressure still held on the brake pedal, start the engine.

^ Did the pedal travel increase as the engine started?

-> Yes

The vacuum function of the brake booster is operating normally. Check for DTCs indicating a fault elsewhere in the system.

-> No

CHECK the vacuum circuit to the brake booster.