GM Service Manual Online
For 1990-2009 cars only

Diagnostic Aids

An inoperative light emitting diode (LED) on the electronic brake control module (EBCM) may cause the EBCM to illuminate an invalid combination of LEDs. This does not, however, indicate that the EBCM is non-functional or needs to be replaced. You may be able to navigate to the correct diagnostic procedure by determining which LED is inoperative and combining the displayed LEDs with an inoperative LED in order to create a valid diagnostic fault display.

For example:

    • The EBCM displays illuminated LFT and FRT LEDs.
    • A technician finds that the MOD LED is inoperative.

A safe assumption to make is that the EBCM is indicating a left, front modulator diagnostic fault.

If using the specified procedure does not indicate a valid fault, or if more than one LED is found to be inoperative, the EBCM may need to be replaced.

Step

Action

Yes

No

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

  1. Turn ON the ignition.
  2. Perform the magnetic reset procedure. Refer to Status Lamp Resetting .

Do all the LEDs on the electronic brake control module (EBCM) illuminate during the reset procedure?

Go to Step 3

Go to Diagnostic Aids

3

Replace the EBCM. Refer to Control Module References for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 4

--

4

  1. Turn ON the ignition.
  2. Observe the LEDs on the EBCM after the ignition has been ON for 10 seconds.

Does the EBCM display only an illuminated green VLT LED?

System OK

Go to Diagnostic System Check - Vehicle