DTC C0288 or C088 Brake Warning Lamp Circuit Shorted to B+. GMC Truck Export Savana 1998

For 1990-2009 cars

### Circuit Description

The red BRAKE warning lamp is supplied ignition voltage through the GAUGES fuse. The BRAKE warning lamp can be illuminated with a ground supplied by the EBCM, Brake Pressure Differential Switch or by the Park Brake Switch.

### Conditions for Setting the DTC

• | High voltage is present on the BRAKE warning lamp circuit when the circuit is expected to be low (lamp commanded on by the EBCM)

• | Anything that keeps the Brake warning lamp circuit high when the lamp is supposed to be illuminated (such as a short to voltage on CKT 33)

### Action Taken When the DTC Sets

No action taken, the ABS is not disabled.

### Conditions for Clearing the DTC

• | Repair the conditions responsible for setting the DTC

• | Use the Scan Tool Clear DTCs function

### Diagnostic Aids

DTC C0288 is usually set by a short to voltage in the wiring between the brake warning lamp and the EBCM.

### Test Description

The numbers below refer to the steps in the diagnostic table:

1. Determines if the BRAKE warning lamp circuit is operating properly when controlled by the EBCM.

2. Determines if the BRAKE warning lamp circuit is operating properly without the EBCM.

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 | Was the ABS Diagnostic System Check performed? | -- | Go to Step 2 | Go to Diagnostic System Check - ABS

2

1. Turn the ignition to RUN.
2. Observe the red BRAKE warning lamp.

Did the BRAKE warning lamp turn on and then off after three seconds?

--

Go to Step 5

Go to Step 3

3

1. Turn the ignition to OFF.
2. Disconnect the 10-way EBCM harness connector from the EBCM.
3. Using a 3 amp fused jumper wire, such as J 36169, connect terminal H of the 10-way EBCM harness connector to ground.
4. Turn the ignition to RUN.

Does the BRAKE warning lamp turn on?

--

Go to Step 6

Go to Step 4

4 | Inspect the Jumper wire Fuse. Is the fuse open? | -- | Go to Step 7 | Go to Step 5

5

Malfunction is intermittent.

Perform the following:

1. Inspect all connectors and harnesses for damage which may result in a short to voltage when all components are connected.
2. Refer to Diagnostic Aids.
3. Perform all necessary repairs.

Is repair complete?

--

Go to Diagnostic System Check - ABS

--

6 | Replace the EBCM. Is repair complete? | -- | Go to Diagnostic System Check - ABS | --
7 | Repair a short to voltage in CKT 33. Is repair complete? | -- | Go to Diagnostic System Check - ABS | --