GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2008 🢒 Optra 🢒 Diagnostic Navigation 🢒 Vehicle Diagnostic Information 🢒 No Communication with Electronic Brake Control Module

No Communication with Electronic Brake Control Module North America

Circuit Description

Battery voltage is supplied to the electronic brake control module (EBCM) through fuse F11 in the instrument panel (I/P) fuse block, to terminal 20 of the EBCM connector. The voltage is present when the ignition switch is in the ON or START position.

This test checks for battery output, proper grounding, blown fuses, a faulty ignition switch, and problems in the circuitry.

Conditions for Running the DTC

The ignition switch is in the On or Start position.

Conditions for Setting the DTC
    • The battery is defective.
    • There is a defective ground connection.
    • A connector is damaged.
    •  A wire is broken or shorted.
    • A fuse is blown.
    • The ignition switch is malfunctioning.

Action Taken When the DTC Sets

The antilock brake system (ABS) action is disabled during the period of low voltage.

Diagnostic Aids

It is very important to perform a thorough inspection of the wiring and the connectors. Failure to do so may result in misdiagnosis, causing part replacement with a reappearance of the malfunction.

Test Description

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

  1. This step determines whether there is voltage at the battery and the high current source.

    2.

  2. This step inspects for voltage at the ignition 1 source.

    3.

  3. This step begins the check for voltage at the EBCM end of the ABS harness.

    4.

  4. This step inspects for a defective ground connection.

    5.

  5. This is an inspection for a defective EBCM connector.

Step

Action

Values

Yes

No

Schematic Reference: Antilock Brake System Schematics

Connector End View Reference: Component Connector End Views

1

Did you perform the Diagnostic System Check - Vehicle?

--

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

Measure the voltage at the battery.

Does the voltage measure within the specified range?

11-14 V

Go to Step 4

Go to Step 3

3

Charge or replace the battery as required.

Did you find and correct the condition?

--

Go to Step 26

--

4

Inspect fuse EF2 in the engine fuse block.

Is the fuse open?

--

Go to Step 5

Go to Step 8

5
  1. Replace fuse EF2.
  2. Turn the ignition to ON.

Is the fuse open?

--

Go to Step 6

Go to Step 14

6
  1. Turn the ignition to OFF.
  2. Remove fuse EF2.
  3. Disconnect the ABS connector from the electronic brake control module (EBCM).
  4. Measure the resistance to ground at terminals 14 and 1.

Is the resistance equal to the specified value?

0 ohms

Go to Step 7

Go to Step 24

7

Repair the short to ground in circuit RD between terminal 1 of the engine fuse block connector C107 and the EBCM connector.

Did you complete the repair?

--

Go to Step 26

--

8

Inspect fuse EF5 in the engine fuse block.

Is the fuse open?

--

Go to Step 9

Go to Step 12

9
  1. Replace fuse EF5.
  2. Turn the ignition to ON.

Is the fuse open?

--

Go to Step 10

Go to Step 14

10

  1. Turn the ignition to OFF.
  2. Remove fuse EF5.
  3. Disconnect the ABS connector from the EBCM.
  4. Measure the resistance to ground at terminal 15.

Is the resistance equal to the specified value?

0 ohms

Go to Step 11

Go to Step 24

11
  1. Test circuit RD between terminal 4 of engine fuse block connector C105 and terminal 2 of the ignition switch.
  2. Test circuit PK from terminal 4 of the ignition switch to fuse F11 in the instrument panel (I/P) fuse block to terminal 20 of the ABS EBCM connector.
  3. Repair any short to ground found in the wiring or the ignition switch.

Did you find and correct the condition?

--

Go to Step 26

--

12

Inspect fuse F11 in the I/P fuse block.

Is the fuse open?

--

Go to Step 13

Go to Step 17

13
  1. Replace fuse F11.
  2. Turn the ignition to ON.

Is the fuse open?

--

Go to Step 15

Go to Step 14

14

Inspect the ABS function.

Is the repair complete?

--

Go to Step 26

--

15

  1. Turn the ignition to OFF.
  2. Remove fuse F11.
  3. Disconnect the ABS connector from the EBCM.
  4. Measure the resistance to ground at terminal 20.

Is the resistance equal to the specified value?

0 ohms

Go to Step 16

Go to Step 24

16

Repair the short to ground in circuit PK fuse F11 of the I/P fuse block and terminal 20 of the ABS harness EBCM connector.

Did you complete the repair?

--

Go to Step 26

--

17
  1. Disconnect the EBCM connector from the EBCM.
  2. Turn the ignition to ON.
  3. Measure the presence of battery voltage between ground and terminal 14, and between ground and terminal 1.

Does the voltage measure within the specified range?

11-14 V

Go to Step 19

Go to Step 18

18
  1. Turn the ignition switch to OFF.
  2. Trace the RD wires between terminals 14 and 1 of the EBCM connector to terminal 1 of connector C107 at the engine fuse block.
  3. Repair the open in this circuit.

Did you complete the repair?

--

Go to Step 26

--

19

Measure the voltage between ground and terminal 20 of the EBCM connector.

Does the voltage measure within the specified range?

11-14 V

Go to Step 21

Go to Step 20

20
  1. Turn the ignition switch to OFF.
  2. Trace circuit BN between terminal 20 of the ABS harness EBCM connector to fuse F11 in the I/P fuse block.
  3. Trace circuit PK from fuse F11 of the I/P fuse block to terminal 4, IG1, of the ignition switch.
  4. Test circuit RD from terminal 2, B1, of the ignition switch to terminal 4 of connector C105 at the engine fuse block and to fuse EF5.
  5. Repair the open in the wiring or possibly bad connector terminal, defective ignition switch, or blown fuse EF5.

Did you find and correct the condition?

--

Go to Step 26

--

21
  1. Turn the ignition to OFF.
  2. Measure the resistance between ground and terminals 26 and 13 of the EBCM connector.

Is the resistance equal to the specified value?

0 ohms

Go to Step 22

Go to Step 25

22

Inspect terminals 20, 13, 14, 1, and 26 of the EBCM connector.

Is there a defective terminal?

--

Go to Step 23

Go to Step 24

23

Repair the defective terminal or replace the connector or wiring harness as required.

Did you complete the repair?

--

Go to Step 26

--

24

Replace the EBCM.

Did you complete the replacement?

--

Go to Step 26

--

25

Repair the defective ground connection.

Did you complete the repair?

--

Go to Step 26

--

26

Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Is the repair complete?

--

Go to Step 2

System OK

No Communication with Electronic Brake Control Module Except North America

Circuit Description

Battery voltage is supplied to the electronic brake control module (EBCM) through fuse F11 in the instrument panel (I/P) fuse block, to terminal 4 of the EBCM connector. The voltage is present when the ignition switch is in the ON or START position.

This test checks for battery output, proper grounding, blown fuses, a faulty ignition switch, and problems in the circuitry.

Conditions for Running the DTC

The ignition switch is in the On or Start position.

Conditions for Setting the DTC
    • The battery is defective.
    • There is a defective ground connection.
    • A connector is damaged.
    •  A wire is broken or shorted.
    • A fuse is blown.
    • The ignition switch is malfunctioning.

Action Taken When the DTC Sets

The antilock brake system (ABS) action is disabled during the period of low voltage.

Diagnostic Aids

It is very important to perform a thorough inspection of the wiring and the connectors. Failure to do so may result in misdiagnosis, causing part replacement with a reappearance of the malfunction.

Test Description

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

  1. This step determines whether there is voltage at the battery and the high current source.

    2.

  2. This step inspects for voltage at the ignition 1 source.

    3.

  3. This step begins the check for voltage at the EBCM end of the ABS harness.

    4.

  4. This step inspects for a defective ground connection.

    5.

  5. This is an inspection for a defective EBCM connector.

Step

Action

Values

Yes

No

Schematic Reference: Antilock Brake System Schematics

Connector End View Reference: Component Connector End Views

1

Did you perform the Diagnostic System Check - Vehicle?

--

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

Measure the voltage at the battery.

Does the voltage measure within the specified range?

11-14 V

Go to Step 4

Go to Step 3

3

Charge or replace the battery as required.

Did you find and correct the condition?

--

Go to Step 26

--

4

Inspect fuse EF2 in the engine fuse block.

Is the fuse open?

--

Go to Step 5

Go to Step 8

5
  1. Replace fuse EF2.
  2. Turn the ignition to ON.

Is the fuse open?

--

Go to Step 6

Go to Step 14

6
  1. Turn the ignition to OFF.
  2. Remove fuse EF2.
  3. Disconnect the ABS connector from the electronic brake control module (EBCM).
  4. Measure the resistance to ground at terminals 32 and 1.

Is the resistance equal to the specified value?

0 ohms

Go to Step 7

Go to Step 24

7

Repair the short to ground in circuit RD between terminal 32 of the engine fuse block connector C107 and the EBCM connector.

Did you complete the repair?

--

Go to Step 26

--

8

Inspect fuse EF5 in the engine fuse block.

Is the fuse open?

--

Go to Step 9

Go to Step 12

9
  1. Replace fuse EF5.
  2. Turn the ignition to ON.

Is the fuse open?

--

Go to Step 10

Go to Step 14

10

  1. Turn the ignition to OFF.
  2. Remove fuse EF5.
  3. Disconnect the ABS connector from the EBCM.
  4. Measure the resistance to ground at terminal 15.

Is the resistance equal to the specified value?

0 ohms

Go to Step 11

Go to Step 24

11
  1. Test circuit RD between terminal 4 of engine fuse block connector C105 and terminal 2 of the ignition switch.
  2. Test circuit PK from terminal 4 of the ignition switch to fuse F11 in the instrument panel (I/P) fuse block to terminal 4 of the ABS EBCM connector.
  3. Repair any short to ground found in the wiring or the ignition switch.

Did you find and correct the condition?

--

Go to Step 26

--

12

Inspect fuse F11 in the I/P fuse block.

Is the fuse open?

--

Go to Step 13

Go to Step 17

13
  1. Replace fuse F11.
  2. Turn the ignition to ON.

Is the fuse open?

--

Go to Step 15

Go to Step 14

14

Inspect the ABS function.

Is the repair complete?

--

Go to Step 26

--

15

  1. Turn the ignition to OFF.
  2. Remove fuse F11.
  3. Disconnect the ABS connector from the EBCM.
  4. Measure the resistance to ground at terminal 4.

Is the resistance equal to the specified value?

0 ohms

Go to Step 16

Go to Step 24

16

Repair the short to ground in circuit PK fuse F11 of the I/P fuse block and terminal 4 of the ABS harness EBCM connector.

Did you complete the repair?

--

Go to Step 26

--

17
  1. Disconnect the EBCM connector from the EBCM.
  2. Turn the ignition to ON.
  3. Measure the presence of battery voltage between ground and terminal 32, and between ground and terminal 1.

Does the voltage measure within the specified range?

11-14 V

Go to Step 19

Go to Step 18

18
  1. Turn the ignition switch to OFF.
  2. Trace the RD wires between terminals 32 and 1 of the EBCM connector to terminal 1 of connector C107 at the engine fuse block.
  3. Repair the open in this circuit.

Did you complete the repair?

--

Go to Step 26

--

19

Measure the voltage between ground and terminal 4 of the EBCM connector.

Does the voltage measure within the specified range?

11-14 V

Go to Step 21

Go to Step 20

20
  1. Turn the ignition switch to OFF.
  2. Trace circuit BN between terminal 4 of the ABS harness EBCM connector to fuse F11 in the I/P fuse block.
  3. Trace circuit PK from fuse F11 of the I/P fuse block to terminal 4, IG1, of the ignition switch.
  4. Test circuit RD from terminal 2, B1, of the ignition switch to terminal 4 of connector C105 at the engine fuse block and to fuse EF5.
  5. Repair the open in the wiring or possibly bad connector terminal, defective ignition switch, or blown fuse EF5.

Did you find and correct the condition?

--

Go to Step 26

--

21
  1. Turn the ignition to OFF.
  2. Measure the resistance between ground and terminals 47 and 16 of the EBCM connector.

Is the resistance equal to the specified value?

0 ohms

Go to Step 22

Go to Step 25

22

Inspect terminals 4, 16, 1, 32, and 47 of the EBCM connector.

Is there a defective terminal?

--

Go to Step 23

Go to Step 24

23

Repair the defective terminal or replace the connector or wiring harness as required.

Did you complete the repair?

--

Go to Step 26

--

24

Replace the EBCM.

Did you complete the replacement?

--

Go to Step 26

--

25

Repair the defective ground connection.

Did you complete the repair?

--

Go to Step 26

--

26

Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Is the repair complete?

--

Go to Step 2

System OK