GM Service Manual Online
For 1990-2009 cars only

Object Number: 307942  Size: MF
ABS Components
Antilock Brake System Schematics
Handling Electrostatic Discharge Sensitive Parts Notice
Data Link Connector Schematics
Power Distribution Schematics
Antilock Brake System Schematics

Circuit Description

Ignition voltage is supplied through terminal   A1 of the Electronic Brake Control Relay. The above condition enables the EBTCM to energize the pull-in coil by completing the ground circuit at connector  C1 terminal  A11 of the EBTCM. The magnetic field created closes the Electronic Brake Control Relay contacts. The magnetic field also allows battery voltage and current through the Electronic Brake Control Relay terminal  C1 to be supplied to the EBTCM through connector  C2 terminal  C and to the brake solenoid valves through  S279.

Conditions for Setting the DTC

DTC C 1215 can set only before the EBTCM commands the Electronic Brake Control Relay on.

DTC C 1215 determines if the Electronic Brake Control Relay energizes when the Electronic Brake Control Relay should not energize. The above malfunction will not allow the Electronic Brake Control Relay to remove power to the ABS/ETS system.

If a second malfunction occurs, that requires the Electronic Brake Control Relay to turn off, the second malfunction cannot be removed if the Electronic Brake Control Relay cannot be controlled. The DTC sets if the malfunction is present for three consecutive drive cycles.

Action Taken When the DTC Sets

    • A malfunction DTC is stored.
    • The ABS/ETS does not disable.

Conditions for Clearing the DTC

    • The condition responsible for setting the DTC no longer exists and the Scan Tool Clear DTCs function is used.
    • 100 drive cycles pass with no DTCs detected.

Diagnostic Aids

Many conditions may cause an intermittent malfunction. Proper use of the scan tool enhanced diagnostic function can be used in order to measure the frequency of the fault. Thoroughly inspect any circuitry that may be causing the intermittent complaint for the following conditions:

    • Backed out terminals
    • Improper mating
    • Improperly formed or damaged terminals
    • Poor terminal-to-wiring connections
    • Rubbed-through wire insulation
    • A broken wire inside the insulation

Clear all of the DTCs after completing the diagnosis. Test drive the vehicle for three drive cycles in order to verify that the DTC does not reset. Use the following procedure in order to complete one drive cycle:

  1. Start the vehicle.
  2. Drive the vehicle over 16 km/h (10 mph).
  3. Stop the vehicle.
  4. Turn the ignition to the OFF position.

Step

Action

Value(s)

Yes

No

1

Was the Diagnostic System Check performed?

--

Go to Step 2

Go to Diagnostic System Check - ABS

2

Are any other DTCs present?

--

Go to Diagnostic Trouble Code (DTC) List for appropriate DTC

Go to Step 3

3

  1. Turn the ignition switch to the OFF position.
  2. Install a scan tool.
  3. Turn the ignition switch to the ON position.
  4. Do not start the engine.

  5. Use the Relay Test function of the scan tool to command the Electronic Brake Control Relay off.

Does the scan tool indicate that the Electronic Brake Control Relay is off and the battery voltage less than or equal to the specified voltage?

5 V

Go to Diagnostic Aids

Go to Step 4

4

  1. Turn the ignition switch to the OFF position.
  2. Disconnect the 24-way EBTCM connector C1.
  3. Disconnect the 8-way EBTCM connector C2.
  4. Turn the ignition switch to the ON position.
  5. Do not start the engine.

  6. Use the J 39200 in order to measure the voltage between the 8-way EBTCM harness connector C2 terminal C and ground.

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

2 V

Go to Step 6

Go to Step 5

5

  1. Turn the ignition switch to the OFF position.
  2. Disconnect the Electronic Brake Control Relay.
  3. Turn the ignition switch to the ON position.
  4. Do not start the engine.

  5. Use the J 39200 in order to measure the voltage between the 8-way EBTCM harness connector C2 terminal C and ground.

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

2 V

Go to Step 10

Go to Step 9

6

  1. Turn the ignition switch to the OFF position.
  2. Inspect the following components:
  3. • The 8-way EBTCM connector C2
    • 8-way EBTCM harness connector C2
  4. Inspect for the following conditions:
  5. • Poor terminal contact
    • Corrosion
    • Damaged terminals.

Is there a condition that may cause a short to voltage?

--

Go to Step 8

Go to Step 7

7

  1. Reconnect the 24-way EBTCM connector C1.
  2. Reconnect the 8-way EBTCM connector C2.
  3. Turn the ignition switch to the ON position.
  4. Do not start the engine.

  5. Use the Relay Test function of the scan tool to command the Electronic Brake Control Relay off.

Does the scan tool indicate that the Electronic Brake Control Relay is off and is the battery voltage less than or equal to the specified voltage?

5 V

Go to Diagnostic Aids

Go to Step 11

8

Replace all of the terminals or the connectors that exhibit signs of poor terminal contact, corrosion, or damaged terminals.

Is the repair complete?

--

Go to Diagnostic System Check - ABS

--

9

Repair the short to voltage in CKT 1633.

Is the repair complete?

--

Go to Diagnostic System Check - ABS

--

10

Replace the Electronic Brake Control Relay. Refer to Electronic Brake Control Relay Replacement .

Is the repair complete?

--

Go to Diagnostic System Check - ABS

--

11

Replace the EBTCM. Refer to Electronic Brake and Traction Control Module Replacement .

Is the repair complete?

--

Go to Diagnostic System Check - ABS

--