GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2005 🢒 Vivant 🢒 Brakes 🢒 Antilock Brake System 🢒 No Communication with Electronic Brake Control Module

Circuit Description

Serial data is transmitted/received by the electronic brake control module (EBCM) through terminal B6. The EBCM is supplied with constant battery feed voltage through terminals A and B, and switched ignition voltage through terminal A11. The EBCM ground is provided through terminal D and C.

Diagnostic Aids

Typical causes of no communication with the EBCM:

    • Poor terminal contact at the EBCM
    • Loss of EBCM ground to terminal D and C
    • Loss of battery voltage at EBCM terminals A and/or B
    • Loss of ignition voltage at EBCM A11
    • Open/grounded data line
    • Data line with high resistance

Step

Action

Value(s)

Yes

No

1

Did you perform the Diagnostic System Check - ABS?

--

Go to Step 2

Go to Diagnostic System Check - ABS

2
  1. Turn the ignition switch OFF.
  2. Disconnect the electronic brake control module (EBCM) harness.
  3. Connect a voltmeter to the EBCM harness terminal B and then to body ground.

Does the voltage measure within the specified range?

B+

Go to Step 4

Go to Step 3

3
  1. Repair the source of the low voltage to terminal B.
  2. Inspect for an open fuse, poor terminal contact, or a grounded wire.

Did you find and correct the condition?

--

System OK

--

4

Connect a voltmeter to the EBCM harness terminal A and then to the body ground.

Does the voltage measure within the specified range?

B+

Go to Step 6

Go to Step 5

5
  1. Repair the source of the low voltage to terminal A.
  2. Inspect for an open fuse, poor terminal contact, or a grounded wire.

Did you find and correct the condition?

--

System OK

--

6
  1. Turn ON the ignition switch.
  2. Connect a voltmeter to the EBCM harness terminal A11 and then to body ground.

Does the voltage measure within the specified range?

B+

Go to Step 8

Go to Step 7

7
  1. Repair the source of the low voltage to terminal A11.
  2. Inspect for an open fuse, poor terminal contact, or a grounded wire.

Did you find and correct the condition?

--

System OK

--

8
  1. Turn the ignition switch OFF.
  2. Connect an ohmmeter to the EBCM harness terminal D and C and then to body ground.

Does the resistance measure less than the specified value?

2 ohms

Go to Step 10

Go to Step 9

9
  1. Repair the source of the high resistance between terminal C and body ground.
  2. Find and inspect the ground location where the circuit is secured to body ground.

Did you find and correct the condition?

--

System OK

--

10
  1. Turn OFF the ignition switch.
  2. Verify the EBCM harness is still disconnected from the EBCM.
  3. Connect an ohmmeter to the EBCM harness terminal B6 and the data link connector (DLC) terminal 7.

Does the resistance measure less than the specified value?

2 ohms

Go to Step 12

Go to Step 11

11

Repair the source the high resistance between terminal B6 and DLC terminal 7.

Did you complete the repair?

--

System OK

--

12
  1. Turn the ignition switch OFF.
  2. Verify the EBCM harness is still disconnected.
  3. Connect an ohmmeter to the EBCM harness terminal B6 and then to body ground.

Does the resistance measure OL, open circuit?

--

Go to Step 14

Go to Step 13

13

Find and repair the short to ground on the data line.

Did you find and correct the condition?

--

System OK

--

14

Replace the EBCM.

Did you complete the replacement?

--

System OK

--