Hydraulic Brake Diagnostic System Check

NOTE: The diagnostic system check will provide the following information:

The identification of the control module(s) which command the system.
The ability of the control module(s) to communicate through the serial data circuit.
The identification of any stored diagnostic trouble codes (DTCs) and their status.

The diagnostic system check will identify the correct procedure for diagnosing the system and where the procedure is located.

Install a scan tool. If the scan tool powers up, go to next step. If the scan tool does not power up, see appropriate BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT.
Turn ON the ignition, with the engine OFF. Attempt to establish communication with the following control modules:
- Electronic Brake Control Module (EBCM).
- Body Control Module (BCM).
If the scan tool communicates with all control modules, go to next step. If the scan tool does not communicate with all control modules, see appropriate BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT.
Select the display DTCs function on the scan tool for the following control modules:
- Electronic Brake Control Module (EBCM).
- Body Control Module (BCM).
If the scan tool displays any DTCs, go to next step. If the scan tool does not display any DTCs, see HYDRAULIC BRAKE SYMPTOMS under TROUBLE SHOOTING.
If the scan tool displays any DTCs which begin with a "U", see appropriate BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT. If the scan tool does not display any DTCs which begin with a "U", go to next step.
If the scan tool displays DTC B1000, see appropriate BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT. If the scan tool does not display DTC B1000, go to next step.
If the scan tool displays DTC P0560 or P0620, see appropriate GENERATORS & REGULATORS article in ELECTRICAL. If scan tool displays DTC C0267, see DTC C0267: BRAKE FLUID LEVEL SWITCH CIRCUIT FAULT under SELF-DIAGNOSTICS. If other DTCs are displayed, see appropriate ANTI-LOCK article.