GM Service Manual Online
For 1990-2009 cars only

Object Number: 421901  Size: LF
ABS Components
Without Traction Control

Circuit Description

The ASR OFF Indicator is controlled by the EBTCM by sending class 2 messages to the Instrument Panel Cluster (IPC). It is turned on when the EBTCM sets a DTC that turns on the ASR OFF indicator. It is also turned on or off when the Accelerator Slip Regulation (ASR) Switch is pressed. The Electronic Brake Traction Control Module (EBTCM) supplies 12 volts to the ASR Switch, when the ASR switch is depressed the EBTCM sees the voltage go low, and that the ASR switch state has changed. When the EBTCM receives that a switch state has changed it turns on or off the ASR and sends a message to the IPC to turn on or off the ASR OFF indicator depending on its previous state.

Diagnostic Aids

    • It is very important that a thorough inspection of the wiring and connectors be performed. Failure to carefully and fully inspect wiring and connectors may result in misdiagnosis, causing part replacement with reappearance of the malfunction.
    • Thoroughly inspect any circuitry that may be causing the complaint for the following conditions:
       - Backed out terminals
       - Improper mating
       - Broken locks
       - Improperly formed or damaged terminals
       - Poor terminal-to-wiring connections
       - Physical damage to the wiring harness
    • The following conditions may cause an intermittent malfunction:
       - A poor connection
       - Rubbed-through wire insulation
       - A broken wire inside the insulation
    • If an intermittent malfunction exists refer to Troubleshooting Procedures in Wiring Systems for further diagnosis.

Test Description

The number(s) below refer to the step number(s) on the diagnostic table.

  1. Checks if EBCM/EBTCM is receiving a ASR switch message from the switch.

  2. Check if the scan tool can turn on and off the indicator lamps in the instrument cluster.

  3. Checks if the EBCM/EBTCM or ASR Switch is at fault.

ASR Off Indicator Inoperative with No DTC Set

Step

Action

Value(s)

Yes

No

DEFINITION: ASR Off indicator is inoperative when attempting to disable traction control. There are no DTC(s) set.

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 RUN position, engine off.
  2. Using a scan tool enter TCS Data List.
  3. While monitoring the TCS On/Off switch status, press and release the ASR On/Off switch.

Does the switch status change from pressed to released as the ASR switch is pressed and released?

--

Go to Step 3

Go to Step 5

3

  1. Using a scan tool in the Instrument Pannel Cluster Special Function.
  2. Go to WOW Instrument Panel in Output Control.
  3. In the WOW mode you can turn on or off the instrument panel indicators.
  4. All indicators will turn ON when commanded on.

Does the ASR OFF indicator turn on then off?

--

Go to Step 11

Go to Step 4

4

  1. Disconnect instrument cluster and connect a test light across the appropraiate power and ground terminals.
  2. Test light OFF, repair open in power or ground circuit to cluster.
  3. Test light ON, check connector for poor connection to Cluster.
  4. If OK, replace the instrument cluster Instrument Cluster Replacement .

Is the instrument cluster replacement complete?

--

Go to Step Diagnostic System Check - ABS

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5

  1. Remove the ASR switch and disconnect the connector. Refer to Electronic Traction Control Switch Replacement
  2. Using a scan tool in ABS/TC Data List read the TCS switch status.
  3. Connect a jumper wire between terminals E and  F of the ASR Switch harness connector.

Does the TCS switch status read pressed with the jumper wire connected?

--

Go to Step 6

Go to Step 7

6

Replace the ASR switch. Refer to Electronic Traction Control Switch Replacement

Is the replacement complete?

--

Go to Diagnostic System Check - ABS

--

7

  1. Turn the ignition switch to the OFF position.
  2. Using J 39200 DMM, measure the resistance between the ASR switch harness connector terminal F and a known good ground.

Is the resistance within the range specified in the value(s) column?

0-5 ohms

Go to Step 9

Go to Step 8

8

Repair CKT 451 for a open or high resistance. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Diagnostic System Check - ABS

--

9

  1. Disconnect the EBTCM Connector C1
  2. Install the J 39700 Universal Pinout box using the J 39700-25 cable adapter to connector C1 only.
  3. Using DMM, measure the resistance between the ASR switch harness connector terminal E and 17 of J 39700
  4. Is the resistace within the range specified in the value(s) column?

0-5 ohms

Go to Step 11

Go to Step 10

10

Repair CKT 1571 for an open or high resistance. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Diagnostic System Check - ABS

--

11

Replace the EBTCM. Refer to Electronic Brake Control Module Replacement

Is the replacement complete?

--

Go to Diagnostic System Check - ABS

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