GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2005 🢒 Optra 🢒 Brakes 🢒 Antilock Brake System 🢒 Brake Warning Indicator Inoperative

Circuit Description

Battery voltage is supplied to the EBD warning lamp with the ignition switch in the ON or START position. The warning lamp can be activated only by the antilock brake system (ABS) control module internally supplying ground to terminal 21.

This procedure checks for a problem in the wiring, a faulty ground, a voltage supply problem, a burned out indicator lamp, or a contact problem in a connector.

Conditions for Setting the DTC
    • A fuse has blown.
    • The indicator lamp has burned out.
    • There is a corroded or broken connector terminal.
    • There is a faulty ground connection.
    • There is a broken wire in a wiring harness.
    • The electronic brake control module (EBCM) is faulty.

Test Description

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

  1. This test checks for any DTCs that may cause the EBD indicator lamp to be inoperative.

    2.

  2. This test verifies an inoperative lamp condition.

    3.

  3. This test inspects for voltage on the lamp circuit.

    4.

  4. This begins a series of tests of the circuit from the indicator lamp to the EBCM and ground.

    5.

  5. This begins a series of tests of the voltage supply circuits that power the indicator lamp.

Step

Action

Values

Yes

No

1

Install the scan tool and check for any DTCs.

Is any DTC set?

--

Go to the chart for the DTC

Go to Step 2

2

  1. Turn the ignition switch to LOCK.
  2. Disconnect the scan tool.
  3. Release the parking brake fully.
  4. Push the brake pedal.
  5. Turn the ignition switch to ON.
  6. Observe the EBD indicator lamp.

Does the lamp illuminate for about 4 seconds and then turn OFF?

--

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3

With the ignition still ON, observe the oil pressure lamp.

Is the oil pressure lamp illuminated?

--

Go to Step 4

Go to Step 19

4

  1. Turn the ignition switch to LOCK.
  2. Disconnect the connector from the electronic brake control module (EBCM).
  3. Connect a jumper from terminal 21 to the grounding bar in the connector.
  4. Turn the ignition switch to ON.

Does the EBD indicator illuminate?

--

Go to Step 5

Go to Step 8

5
  1. Turn the ignition switch to LOCK.
  2. Examine terminals 19 and 21 at the EBCM connector on both the antilock brake system (ABS) wiring harness and on the EBCM.

Is there a poor connection at any of these terminals?

--

Go to Step 6

Go to Step 7

6

Repair the faulty terminals or replace the ABS unit as required.

Did you complete the repair?

--

System OK

--

7

Replace the ABS unit.

Did you complete the replacement?

--

System OK

--

8
  1. Turn the ignition switch to LOCK.
  2. Disconnect the wire from the negative battery terminal.
  3. Measure the resistance between the negative battery wire which is attached to ground, and the shorting bar in the EBCM connector.

Does the resistance measure equal to the specified value?

0 ohms

Go to Step 10

Go to Step 9

9

Repair the open or high resistance in the circuit from the EBCM connector, terminal 19 to ground G106.

Did you complete the repair?

--

System OK

--

10
  1. Remove the instrument panel (I/P) cluster.
  2. Remove and inspect the EBD indicator bulb.

Is the bulb burned out?

--

Go to Step 11

Go to Step 12

11
  1. Replace the EBD indicator bulb.
  2. Install the I/P cluster.

Did you complete the repair?

--

System OK

--

12

Inspect the continuity at the I/P cluster connector terminal A1.

Does the ohmmeter show the specified value?

0 ohms

Go to Step 14

Go to Step 13

13

Repair the contact at the I/P cluster connector terminal A1.

Did you complete the repair?

--

System OK

--

14

Inspect the wiring harnesses and connectors in circuit PPL/WHT from the I/P cluster terminal A1 to terminal 21 of the EBCM connector.

Does the ohmmeter show the specified value?

∞

Go to Step 15

Go to Step 16

15

Repair the open or high resistance found.

Did you complete the repair?

--

System OK

--

16

Inspect for continuity between terminal 19 of the ABS connector and ground G106.

Does the ground connection equal the specified value?

0 ohms

Go to Step 17

Go to Step 18

17

Replace the ABS unit.

Did you complete the replacement?

--

System OK

--

18

Repair the continuity problem between terminal 19 of the EBCM connector and ground G106.

Did you complete the repair?

--

System OK

--

19

  1. Turn the ignition switch to LOCK.
  2. Inspect fuse F4 in the I/P fuse block.

Is this fuse open?

--

Go to Step 20

Go to Step 21

20

Replace fuse F4.

Did you complete the replacement?

--

System OK

--

21

Inspect fuse F5 in the engine fuse block.

Is this fuse open?

--

Go to Step 22

Go to Step 23

22

Replace fuse EF5.

Did you complete the replacement?

--

System OK

--

23

Measure the voltage at terminal 2 of the ignition switch connector by backprobing.

Does the voltage measure within the specified range?

11-14 V

Go to Step 25

Go to Step 24

24
  1. Inspect circuit RED between terminal 4 of C105 at the engine fuse block and terminal 2 of the ignition switch for continuity.
  2. Repair any open or high resistance found.

Did you complete the repair?

--

System OK

--

25
  1. Turn the ignition switch to ON.
  2. Backprobe terminal 4 (PNK) of the ignition switch connector.

Is the voltage within the specified range?

11-14 V

Go to Step 27

Go to Step 26

26

Replace the ignition switch.

Did you complete the replacement?

--

System OK

--

27
  1. Turn the ignition switch to LOCK.
  2. Inspect circuit PNK from terminal 4 of the ignition switch to fuse F4 in the I/P fuse block.

Does the ohmmeter show the specified value?

∞

Go to Step 28

Go to Step 29

28

Repair the open or the high resistance.

Did you complete the repair?

--

System OK

--

29
  1. Remove the instrument cluster.
  2. Inspect circuit PNK from fuse F4 to terminal B15 or A19 of the I/P cluster connector A.
  3. Repair any open or high resistance found in a wiring harness, splice pack, or connector.

Did you complete the repair?

--

System OK

--