GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2004 🢒 Montana - 4WD 🢒 Brakes 🢒 Hydraulic Brakes 🢒 Diagnostic System Check - Hydraulic Brakes

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. Lack of communication may be due to a partial malfunction of the serial data circuit or due to a total malfunction of the serial data circuit. The specified procedure will determine the particular condition.

    2.

  2. The presence of DTCs which begin with "U" indicate some other module is not communicating. The specified procedure will compile the available information before tests are performed.

Step

Action

Yes

No

1

Install a scan tool.

Does the scan tool power up?

Go to Step 2

Go to Scan Tool Does Not Power Up in Data Link Communication

2

  1. Turn ON the ignition, with the engine OFF.
  2. Attempt to establish communication with the following control modules:
    3. • Electronic brake control module (EBCM)
    • Instrument panel cluster (IPC)

Does the scan tool communicate with all control modules?

Go to Step 3

Go to Scan Tool Does Not Communicate with Class 2 Device in Data Link Communication

3

Select the display DTCs function on the scan tool for the following control modules:

    • Electronic brake control module (EBCM)
    • Instrument panel cluster (IPC)

Does the scan tool display any DTCs?

Go to Step 4

Go to Symptoms - Hydraulic Brakes

4

Does the scan tool display any DTCs which begin with a "U"?

Go to Scan Tool Does Not Communicate with Class 2 Device in Data Link Communication

Go to Step 5

5

Does the scan tool display DTC B1000?

Go to Diagnostic Trouble Code (DTC) List in Body Control System

Go to Diagnostic Trouble Code (DTC) List in Antilock Brake System