GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 1998 🢒 Firefly (Canada) 🢒 Brakes 🢒 Antilock Brake System 🢒 No Communication with Electronic Brake Control Module

Object Number: 424149 Size: MF
ABS Components
Antilock Brake System Schematics
Handling ESD Sensitive Parts Notice

Circuit Description

Serial data is transmitted/received by the EBCM through terminal A1. The EBCM is supplied switched ignition voltage through connector C1 terminal A9 and battery feed voltage through connector C1 terminal B12. The EBCM ground is provided through connector C2 terminal D.

Diagnostic Aids

Communication with the EBCM is not possible when excessive resistance exists in the following components:

    • The ground
    • The power supply circuits

If communication with the EBCM is not possible, perform the following actions:

    • Verify that the EBCM ground connection is good.
    • Verify that no excessive resistance exists in any of the power supply circuits.

Test Description

  1. This test determines if the EBCM is sending data.

    2.

  2. This test checks for a serial data link malfunction.

    3.

  3. This test checks for high resistance in the EBCM ground circuit.

    4.

  4. This test checks for an open in the EBCM battery feed circuit.

    5.

  5. This test checks for an open in the EBCM switched ignition circuit.

    6.

  6. This test checks for an open or high resistance in the EBCM ground circuit.

    7.

  7. This test checks for an open or high resistance in the EBCM battery feed circuit.

    8.

  8. This test checks for an open or high resistance in the EBCM switched ignition circuit.

    9.

  9. This test checks for an open or high resistance in the EBCM serial data circuit.

    10.

  10. This test checks for a short to ground in the EBCM serial data circuit.

    11.

  11. This test checks for a short to ground in the EBCM battery feed circuit.

    12.

  12. This test isolates the short to ground to either the wiring or the EBCM.

    13.

  13. This test checks for a short to ground in the EBCM switched ignition circuit.

    14.

  14. This test isolates the short to ground to either the wiring or the EBCM.

No Communication With EBCM

Step

Action

Value(s)

Yes

No

Important: Zero the J 39200 test leads before making any resistance measurements. Refer to the J 39200 user's manual.

1

Was the ABS Diagnostic System Check performed?

--

Go to Step 2

Go to Diagnostic System Check - ABS

2

  1. Verify that the EBCM connector is properly connected.
  2. Install a Scan Tool.
  3. Turn the ignition switch to the ON position.

    4. Do not start the engine.

  4. Select the ABS portion of the chassis application on the Scan Tool.
  5. Select Data Display on the Scan Tool.
  6. Select ABS Data

Is data being received from the EBCM?

--

Go to Step 16

Go to Step 3

3

Read the Scan Tool display.

Does the Scan Tool display the message "No Communication With Vehicle. Check DLC Connector"?

--

Go to Data Link Connector System Check in Wiring Systems

Go to Step 4

4

Verify the correct connection of the Scan Tool to the DLC.

Is connection of the Scan Tool to the DLC correct?

--

Go to Step 5

Go to Step 27

5
  1. Turn the ignition switch to the OFF position.
  2. Remove and inspect the fuse block HAZARD Fuse (15A).

Is the fuse open?

--

Go to Step 19

Go to Step 6

6
  1. Install the fuse block HAZARD Fuse (15A).
  2. Remove the fuse block DEF Fuse (20A).

Is the fuse open?

--

Go to Step 22

Go to Step 7

7

  1. Install the fuse block DEF Fuse (20A).
  2. Disconnect the EBCM connector.
  3. Use the J 39200 in order to measure the resistance between the EBCM connector terminal D and ground.

Is the resistance within the specified range?

0-2 ohms

Go to Step 8

Go to Step 28

8

  1. Disconnect the EBCM connector.
  2. Use the J 39200 in order to measure voltage between the EBCM connector terminal B12 and ground.

Is the voltage equal to or greater than the specified voltage?

10 V

Go to Step 9

Go to Step 29

9

  1. Turn the ignition switch to the ON position.

    2. Do not start the engine.

  2. Use the J 39200 in order to measure voltage between the EBCM connector terminal A9 and ground.

Is the voltage equal to or greater than the specified voltage?

10 V

Go to Step 10

Go to Step 30

10

  1. Turn the ignition switch to the OFF position.
  2. Disconnect the negative battery cable.
  3. Disconnect the positive battery cable.
  4. Use the J 39200 in order to measure the resistance between the EBCM connector terminal D and the negative battery cable terminal.

Is the resistance within the specified range?

0-2 ohms

Go to Step 11

Go to Step 31

11

Use the J 39200 in order to measure the resistance between the EBCM connector terminal B12 and the positive battery cable terminal.

Is the resistance within the specified range?

0-2 ohms

Go to Step 12

Go to Step 32

12

  1. Turn the ignition switch to the ON position.

    2. Do not start the engine.

  2. Use the J 39200 in order to measure the resistance between the EBCM connector terminal A9 and the positive battery cable terminal.

Is the resistance within the specified range?

0-2 ohms

Go to Step 13

Go to Step 33

13

  1. Turn the ignition switch to the OFF position.
  2. Use the J 39200 in order to measure the resistance between the EBCM connector terminal A1 and the DLC terminal 9.

Is the resistance within the specified range?

0-2 ohms

Go to Step 14

Go to Data Link Connector System Check in Wiring Systems

14

Use the J 39200 in order to measure the resistance between the EBCM connector terminal A1 and ground.

Is the resistance within the specified range?

OL (Infinite)

Go to Step 15

Go to Data Link Connector System Check in Wiring Systems

15
  1. Inspect the following components:
    2. • The EBCM connector
    • The negative battery cable
    • The positive battery cable
  2. Inspect the components for the following conditions:
    3. • Poor terminal contact
    • Terminal corrosion
    • Damaged terminals

Are there signs of poor terminal contact, terminal corrosion, or damaged terminals?

--

Go to Step 34

Go to Step 40

16
  1. Connect the Scan Tool .
  2. Select DTCs.

Does the Scan Tool display any current DTCs?

--

Refer to the applicable DTC table

Go to Step 17

17
  1. Turn the ignition switch to the OFF position.
  2. Wait for ten seconds.
  3. Turn the ignition switch to the ON position.

    4. Do not start the engine.

  4. Observe the amber ABS warning indicator.

Does the amber ABS warning indicator turn on for three seconds and then turn off?

--

Go to Step 18

Go to the appropriate symptom table

18
  1. Connect the Scan Tool .
  2. Select DTC History.

Does the Scan Tool display any history DTCs?

--

Go to Step 41

Go to Step 42

19

  1. Replace the fuse block HAZARD Fuse (15A) with a known good fuse (20A).
  2. Wait for ten seconds.
  3. Remove and inspect the fuse.

Is the fuse open?

--

Go to Step 20

Go to Step 36

20

  1. Disconnect the EBCM connector.
  2. Replace the fuse block HAZARD Fuse (15A) with a known good fuse (20A).
  3. Wait for ten seconds.
  4. Remove and inspect the fuse block HAZARD Fuse (15A).

Is the fuse open?

--

Go to Step 35

Go to Step 21

21
  1. Inspect the WHT/GRN wire between the junction block and the EBCM for physical damage.

    2. Physical damage may cause a short to ground with the EBCM connector connected.

  2. Inspect the EBCM connector and the EBCM harness for physical damage.

    3. Physical damage may cause a short to ground with the EBCM connector connected.

  3. Reconnect the EBCM connector.
  4. Reinstall the fuse block HAZARD Fuse (15A).
  5. Wait for ten seconds.
  6. Remove and inspect the fuse block HAZARD Fuse (15A).

Is the fuse open?

--

Go to Step 26

Go to Step 39

22

  1. Replace the fuse block DEF Fuse (20A) with a known good Fuse (20A).
  2. Turn the ignition switch to the ON position.

    3. Do not start the engine.

  3. Wait for ten seconds.
  4. Turn the ignition switch to the OFF position.
  5. Remove and inspect the DEF Fuse (20A).

Is the fuse open?

--

Go to Step 23

Go to Step 38

23

  1. Turn the ignition switch to the OFF position.
  2. Disconnect the EBCM connector.
  3. Replace the fuse block DEF Fuse (20A) with a known good fuse (20A).
  4. Turn the ignition to the ON position.

    5. Do not start the engine.

  5. Wait for ten seconds.
  6. Turn the ignition switch to the OFF position.
  7. Remove and inspect the DEF Fuse (20A).

Is the fuse open?

--

Go to Step 37

Go to Step 24

24
  1. Inspect the YEL/GRN wire between the junction block and the EBCM for physical damage.

    2. Physical damage may cause a short to ground with the EBCM connector connected.

  2. Reconnect the EBCM connector.
  3. Reinstall the fuse block DEF Fuse (20A).
  4. Turn the engine to the ON position.

    5. Do not start the engine.

  5. Wait for ten seconds.
  6. Turn the ignition switch to the OFF position.
  7. Remove and inspect the fuse block DEF Fuse (20A).

Is the fuse open?

--

Go to Step 25

Go to Step 39

25
  1. Replace the EBCM.
  2. Replace the fuse block DEF Fuse (20A) with a known good fuse (20A).

Is the repair complete?

--

Go to Diagnostic System Check - ABS

--

26
  1. Replace the EBCM.
  2. Replace the fuse block HAZARD Fuse (15A) with a known good fuse (15A).

Is the repair complete?

--

Go to Diagnostic System Check - ABS

--

27

Disconnect and reconnect the Scan Tool in order to ensure a good connection.

Is the Scan Tool correctly connected?

--

Go to Diagnostic System Check - ABS

--

28

Repair the open or high resistance in the BLK wire between the EBCM and G102.

Is the repair complete?

--

Go to Diagnostic System Check - ABS

--

29

Repair the open or high resistance in the WHT/GRN wire between the junction block and the EBCM.

Is the repair complete?

--

Go to Diagnostic System Check - ABS

--

30

Repair the open or high resistance in the YEL/GRN wire between the junction block and the EBCM.

Is the repair complete?

--

Go to Diagnostic System Check - ABS

--

31

Repair the open or high resistance in any of the following components:

    • The negative battery cable
    • The negative battery cable terminals
    • The negative battery cable connections

Is the repair complete?

--

Go to Diagnostic System Check - ABS

--

32

Repair the high resistance in the WHT/GRN wire between the junction block and the EBCM or the voltage feed circuits for the fuse block HAZARD Fuse (15A).

Is the repair complete?

--

Go to Diagnostic System Check - ABS

--

33

Repair the open or high resistance in one of the following circuits:

    • The YEL/GRN wire between the junction block and the EBCM.
    • The power feed circuits to the fuse block. Refer to Power Distribution in Wiring Systems.

Is the repair complete?

--

Go to Diagnostic System Check - ABS

--

34

Replace the terminals or the connectors that exhibit the following conditions:

    • Poor terminal contact
    • Terminal corrosion
    • Damaged terminals

Is the repair complete?

--

Go to Diagnostic System Check - ABS

--

35

Repair the short to ground in the WHT/GRN wire between the junction block and the EBCM.

Is the repair complete?

--

Go to Step 19

--

36

Reinstall the fuse block HAZARD Fuse (15A).

Is the installation complete?

--

Go to Diagnostic System Check - ABS

--

37

Repair the short to ground in the YEL/GRN wire between the junction block and the EBCM.

Is the repair complete?

--

Go to Step 22

--

38

Reinstall the fuse block DEF Fuse (20A).

Is the installation complete?

--

Go to Diagnostic System Check - ABS

--

39

The malfunction is intermittent or not present at this time.

Refer to Diagnostic Process for more information.

Is the action complete?

--

System OK

--

40

Replace the EBCM. Refer to Electronic Brake Control Module Replacement .

Is the repair complete?

--

Go to Diagnostic System Check - ABS

--

41

Review the Enhanced Diagnostics information in the Scan Tool manual.

Is the action complete?

--

Go to Diagnostic System Check - ABS

--

42

The system is good.

Refer to Diagnostic Process to further diagnose customer concern.

Is the action complete?

--

Go to Diagnostic System Check - ABS

--