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 1214 can set anytime after the EBTCM commands the Electronic Brake Control Relay on. The command occurs during the three second bulb check.

DTC C 1214 monitors the availability of current/voltage to the motors and solenoids.

The above malfunction indicates voltage is not available. The malfunction will not allow ABS/ETS operation.

Action Taken When the DTC Sets

    • A malfunction DTC stores.
    • The ABS/ETS disables.
    • The amber ABS/ETS warning indicators turn on.
    • The red BRAKE warning indicator turns on if the rear piston in the ABS brake motor pack is not in the home position.

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

Vibration and Temperature Effects

    • Use the following procedure in order to inspect for vibration effects by performing the Relay Test function of the Scan Tool:
        1. With the Relay Test commanded on, lightly tap the top and sides of the Electronic Brake Control Relay while monitoring the Electronic Brake Control Relay voltage.
        2. If the Electronic Brake Control Relay voltage changes significantly, replace the Electronic Brake Control Relay. Refer to Electronic Brake Control Relay Replacement
    • If DTC C1214 only sets when the vehicle is initially started in cold ambient conditions (temperature less than 0°C (32°F)), replace the Electronic Brake Control Relay. Refer to Electronic Brake Control Relay Replacement

Step

Action

Value(s)

Yes

No

1

Was the Diagnostic System Check performed?

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Go to Step 2

Go to Diagnostic System Check - ABS

2

  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.

    Use the scan tool in order to read the DTCs.

Is DTC C1216 present (either as a current DTC or a history DTC)?

--

Go to DTC C1216 Brake Control Relay Coil Circuit Open

Go to Step 3

3

  1. Select Data List on the scan tool.
  2. Select and observe EBTCM Battery Voltage.

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

10 V

Go to Step 4

Go to Charging System Check

4

  1. Turn the ignition switch to the OFF position.
  2. Disconnect the 24-way EBTCM connector  C1.
  3. Connect a fused jumper wire with a 3A fuse between the 24-way EBTCM harness connector  C1 terminal A11 and ground.
  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 equal to or greater than the specified voltage?

10 V

Go to Step 5

Go to Step 10

5

  1. Turn the ignition switch to the OFF position.
  2. Disconnect the fused wire jumper.
  3. Disconnect the Electronic Brake Control Relay.
  4. Use the J 39200 in order to measure the resistance between the Electronic Brake Control Relay harness connector terminal A2 and the EBTCM harness connector C2 terminal C.

Is the resistance within the specified range?

0-2 ohms

Go to Step 6

Go to Step 19

6

  1. Disconnect the negative battery cable.
  2. Disconnect the positive battery cable.
  3. Use the J 39200 in order to measure the resistance between the positive battery cable terminal and the Electronic Brake Control Relay harness connector terminal C1.

Is the resistance within the specified range?

0-2 ohms

Go to Step 7

Go to Step 20

7

  1. Connect a jumper wire between the Electronic Brake Control Relay harness connector terminal C2 to the ground.
  2. Connect a fused jumper wire with a 3A fuse between the Electronic Brake Control Relay terminal A1 and the battery voltage.
  3. Use the J 39200 in order to measure the resistance across the Electronic Brake Control Relay terminal C1 and terminal A2.

Is the resistance within the specified range?

0-2 ohms

Go to Step 8

Go to Step 22

8

  1. Turn the ignition switch to the OFF position.
  2. Inspect the following components:
  3. • The 24-way EBTCM connector C1
    • The 8-way EBTCM connector C2
    • The 24-way EBTCM harness connector C1
    • The 8-way EBTCM harness connector C2
    • The Electronic Brake Control Relay and Harness Connector
  4. Inspect the following components:
  5. • The positive and negative battery terminals
    • The positive and negative battery cable terminals
  6. Inspect all of the above components for signs of the following conditions:
  7. • Damage
    • Poor connection
    • Poor terminal contact

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

--

Go to Step 17

Go to Step 9

9

  1. Remove all of the jumpers.
  2. Reconnect the EBTCM connector C1 and connector C2.
  3. Reconnect the Electronic Brake Control Relay
  4. Reconnect the positive battery cable.
  5. Reconnect the negative battery cable.
  6. Turn the ignition switch to the ON position.
  7. Do not start the engine.

  8. Use the scan tool in order to look for current DTCs.

Does DTC C1214 set as a current DTC?

--

Go to Step 23

Go to Diagnostic Aids

10

  1. Turn the ignition switch to the OFF position.
  2. Disconnect the negative battery cable.
  3. Disconnect the positive battery cable.
  4. Turn the ignition switch to the ON position.
  5. (This action completes the ignition circuit to the Electronic Brake Control Relay.)

  6. Use the J 39200 in order to measure the resistance between the 24-way EBTCM harness connector C1 terminal A11 and the positive battery cable terminal.

Is the resistance within the specified range?

70-95 ohms

Go to Step 11

Go to Step 14

11

Use the J 39200 in order to measure the voltage between the positive battery terminal and the negative battery terminal.

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

10 V

Go to Step 12

Go to Charging System Check

12

  1. Turn the ignition switch to the OFF position.
  2. Reconnect the positive battery cable.
  3. Reconnect the negative battery cable.
  4. Disconnect the Electronic Brake Control Relay.
  5. Use the J 39200 in order to measure the voltage between the Electronic Brake Control Relay harness connector terminal C1 and ground.

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

10 V

Go to Step 13

Go to Step 20

13

Use the J 39200 in order to measure the resistance between the Electronic Brake Control Relay harness connector terminal A2 and the 8-way EBTCM harness connector C2 terminal C.

Is the resistance within the specified range?

0-2 ohms

Go to Step 7

Go to Step 19

14

  1. Disconnect the Electronic Brake Control Relay.
  2. Use the J 39200 in order to measure the resistance between the Electronic Brake Control Relay terminal A1 and the Electronic Brake Control Relay terminal C2.

Is the resistance within the specified range?

70-95 ohms

Go to Step 15

Go to Step 22

15

Use the J 39200 in order to measure the resistance between the Electronic Brake Control Relay harness connector terminal C2 and the 24-way EBTCM harness connector C1 terminal A11.

Is the resistance within the specified range?

0-2 ohms

Go to Step 16

Go to Step 18

16

Use the J 39200 in order to measure the resistance between the Electronic Brake Control Relay harness connector terminal A1 and the positive battery cable terminal.

Is the resistance within the specified range?

0-2 ohms

Go to Step 8

Go to Step 21

17

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

Is the repair complete?

--

Go to Diagnostic System Check - ABS

--

18

Repair the open or high resistance in CKT 1632.

Is the repair complete?

--

Go to Diagnostic System Check - ABS

--

19

Repair the open or high resistance in CKT 1633.

Is the repair complete?

--

Go to Diagnostic System Check - ABS

--

20

Repair the open or high resistance in CKT 102.

Is the repair complete?

--

Go to Diagnostic System Check - ABS

--

21

Repair the open or high resistance in the following components as necessary:

    • CKT 1339
    • CKT 300
    • The ignition switch
    • The battery feed CKT 142 to the ignition switch

Is the repair complete?

--

Go to Diagnostic System Check - ABS

--

22

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

Is the repair complete?

--

Go to Diagnostic System Check - ABS

--

23

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

Is the repair complete?

--

Go to Diagnostic System Check - ABS

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