Circuit/System Verification

WARNING: This page is about a different car, the 2017 GMC Acadia. However, it is still accessible from the selected car via links, so may be relevant.

Ignition ON.
Verify that DTCs P0556, P0557, or P0558 are not set.
- If the DTC is set
  Refer to DTC P0556, P0557, or P0558 .
- If the DTC is not set
Verify that the brake booster vacuum system has no damage, leakage or incorrect installation.
- If damage, leakage or incorrect installation is found
  Refer to Brake Assist System Diagnosis .
- If the inspection is OK
Test or replace the B19B Brake Booster Vacuum Sensor.
Verify the DTC does not set while operating the vehicle under the Conditions for Running the DTC.
- If the DTC sets
  Replace the K20 Engine Control Module.
- If the DTC does not set
All OK.