GM Service Manual Online
For 1990-2009 cars only

Object Number: 337261  Size: SF
ABS Components
Antilock Brake System Schematics

Circuit Description

The traction control system uses the antilock brake system in conjunction with the PCM fuel and ignition controls to limit drive wheel slippage during acceleration. The PCM controlled portion of the traction control system reduces engine torque by performing one or both of the following actions:

    • Retarding the spark timing and alternating the air/fuel ratio
    • Shutting off up to three injectors

The EBCM/EBTCM sends a torque request to the PCM via a Pulse Width Modulated (PWM) signal requesting the desired torque level for proper traction control system operation (CKT 463). The PCM then provides a delivered torque PWM signal (CKT 464) informing the EBCM/EBTCM how much actual torque the engine produces.

Conditions for Setting the DTC

DTC C1323 will set when one of the following conditions occurs:

    • A malfunction exists in the delivered torque circuit (CKT 464).
    • The signal is out of range.

Action Taken When the DTC Sets

    • A malfunction DTC stores.
    • The TCS disables.
    • The amber TCS indicator turns on.

Conditions for Clearing the DTC

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

Diagnostic Aids

Use the enhanced diagnostic function of the Scan Tool in order to measure the frequency of the malfunction. Refer to the Scan Tool manual or Scan Tool Diagnostics located in this section for the procedure.

Thoroughly inspect any circuitry that may cause the intermittent complaint for the following conditions:

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

Important: Zero the J 39200 test leads before making any resistance measurements.

Step

Action

Value(s)

Yes

No

1

Was the Diagnostic System Check performed?

--

Go to Step 2

Go to Diagnostic System Check - ABS

2

  1. Turn the ignition switch to the OFF position.
  2. Disconnect the PCM.
  3. Turn the ignition switch to the ON position.
  4. Use a J 39200 DMM in order to measure the voltage between the delivered torque control circuit at the PCM harness connector and ground.

Is the voltage close to the specified value?

10.0-14.0 V

Go to Step 3

Go to Step  6

3

  1. Connect the J 39200 DMM between the delivered torque control circuit at the PCM harness connector and ground.
  2. Turn the ignition switch ON.
  3. Monitor the current reading on the J 39200 DMM for at least 2 minutes.

Does the current reading remain between the specified values?

0.001-0.5A

(1-500mA)

Go to Step  11

Go to Step  4

4

  1. Turn the ignition switch to the OFF position.
  2. Disconnect the EBTCM. Leave the PCM disconnected.
  3. Turn the ignition switch to the ON position.
  4. Use the J 39200 DMM in order to measure the voltage between the delivered torque control circuit and ground.

Is the voltage equal to the specified value?

0V

Go to Step 10

Go to Step 5

5

Locate and repair the short to voltage in the delivered torque control circuit.

Is the repair complete?

--

Go to Step  16

--

6

  1. Turn the ignition switch to the OFF position.
  2. Inspect the ignition feed fuse to the EBTCM.

Is the fuse blown?

--

Go to Step 7

Go to Step 8

7

  1. Locate and repair the short to ground in the ignition feed circuit for the EBTCM.
  2. Replace the fuse.

Is the repair complete?

--

Go to Step  16

--

8

  1. Disconnect the EBTCM.
  2. Turn the ignition switch to the ON position.
  3. Measure the voltage between the ignition feed circuit for the EBTCM and ground.

Is the voltage near the specified value?

10.0-14.0 V

Go to Step 9

Go to Step 13

9

  1. Inspect the delivered torque control circuit for an open or a short to ground.
  2. Repair the delivered torque control circuit, as needed.

Did you find and repair an open or short to ground?

Go to Step  16

Go to Step 10

10

  1. Inspect the delivered torque control circuit for the following conditions:
  2. • A poor connection at the PCM
    • A poor connection at the EBTCM
  3. Inspect the EBTCM ignition feed circuit for a poor connection at the EBTCM.
  4. Replace any loose terminals, as needed.

Did you find and repair a poor connection?

--

Go to Step  16

Go to Step 14

11

  1. Turn the ignition switch to the OFF position.
  2. Disconnect connector C101.
  3. Use a J 36169-A in order to connect the TCS delivered torque circuit across the connector C101.
  4. Use a J 39200 DMM in order to measure the frequency between the TCS delivered torque circuit and ground.
  5. Turn the ignition switch to the RUN position.
  6. Observe the frequency on the J 39200 DMM.

Is the frequency within the specified range?

120-135Hz

Go to Diagnostic Aids

Go to Step 12

12

  1. Inspect the delivered torque control circuit for a poor connection at the PCM.
  2. If there is a poor connection, replace the loose terminal.

Did you find and repair a poor connection?

--

Go to Step  16

Go to Step 15

13

Locate and repair an open in the ignition feed circuit to the EBTCM.

Is the repair complete?

--

Go to Step  16

Go to Step 15

14

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

Is the repair complete?

--

Go to Step  16

--

15

  1. Replace the PCM.
  2. Program the PCM. Refer to Powertrain Control Module Replacement/Programming .

Is the repair complete?

--

Go to Step  16

--

16

  1. Operate the vehicle within the conditions for setting the DTC.
  2. Use a Scan Tool in order to monitor for DTC C1323.

Does the scan tool indicate the DTC C1323 failed?

--

Go to Step  2

Go to Diagnostic System Check - ABS