GM Service Manual Online
For 1990-2009 cars only

Object Number: 233583  Size: MF
ABS Components
Antilock Brake System Schematics

Circuit Description

The ABS ACTIVE indicator lamp is connected to the IG-COIL METER fuse through CKT 8B01. This circuit is hot in ON and START ignition switch positions. The Electronic Brake Control Module (EBCM) turns ON the ABS ACTIVE by grounding CKT 9W01 and 6C01.

When the ignition switch is turned to the ON position, the EBCM turns ON the ABS ACTIVE indicator for 3 seconds for a bulb check. Whenever the vehicle is involved in an ABS event, the EBCM tuns ON the ABS ACTIVE indicator for the duration of the event (and 1-2 seconds after an ABS event), notifying the driver that ABS is in operation.

Diagnostic Aids

Thoroughly inspect any circuitry that may cause the intermittent 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
    • Short to ground between EBCM and the ABS ACTIVE indicator lamp (CKT 9W01 and/or CKT 6C01)

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

Step

Action

Value(s)

Yes

No

1

Was the Diagnostic System Check performed?

--

Go to Step 2

Go to Diagnostic System Check

2

  1. Turn ignition switch to LOCK.
  2. Disconnect the EBCM connector C1.
  3. Turn the ignition switch to ON.

Is the ABS ACTIVE indicator lamp OFF?

--

Go to Step 3

Go to Step 4

3

  1. Turn the ignition switch to LOCK.
  2. Reconnect the EBCM connector C1.
  3. Turn the ignition switch to ON and observe the ABS ACTIVE indicator.

Did the ABS ACTIVE indicator light for 3 seconds then turn OFF?

--

Go to Step 6

Go to Step 5

4

Repair the short to ground in CKT 6C01 or 9W01 between the EBCM harness connector C1 terminal D4 and I/P gauge cluster harness connector  C3 terminal 6.

Is the repair complete?

--

Go to Step 7

--

5

Inspect EBCM connector C1 for possible short to ground in terminal D4. If OK, replace the EBCM.

Is the repair complete?

--

Go to Step 7

--

6

Malfunction not present at this time. Refer to Diagnostic Aids for additional information regarding possible intermittent condition.

Is the repair complete?

--

Go to Step 7

--

7

  1. Reconnect the EBCM (if disconnected).
  2. Turn the ignition switch ON and observe the ABS ACTIVE indicator.

Did the ABS ACTIVE indicator light for 3 seconds then turn OFF?

--

System OK

Go to Diagnostic System Check