GM Service Manual Online
For 1990-2009 cars only

Object Number: 222434  Size: SF
ABS Components
Antilock Brake System Schematics

Circuit Description

The Electronic Brake Control Module (EBCM) receives a voltage signal from the left front wheel speed sensor through terminal 17 and terminal 18. As a toothed reluctor wheel ring passes the wheel speed sensor, changes in the electromagnetic field cause the wheel speed sensor to produce a small AC voltage. This voltage's frequency is proportional to the wheel speed.

Conditions for Setting the DTC

    • DTC C0035 will set when the EBCM detects the following conditions:
       - An open
       - A short to voltage
       - A short to ground in CKT 830
    • DTC C0035 can be set anytime.

Action Taken When the DTC Sets

    • A malfunction DTC stores.
    • The ABS disables.
    • The ABS warning indicator turns ON.

Conditions for Clearing the DTC

The condition responsible for setting the DTC no longer exists and the Scan Tool Clear DTCs function is used.

Diagnostic Aids

Inspect the following items when diagnosing this part of the Antilock Brake System (ABS):

    • Faulty electrical circuits between the left front wheel speed sensor and the EBCM. These faults include the following:
       - Open and or high resistance
       - Short to voltage
       - Short to ground
    • Faulty left front wheel speed sensor (out of range resistance).

An intermittent malfunction is most likely caused by the following:

    • A poor connection rubbed through the wire insulation
    • A wire that is broken inside the insulation

Inspect the harness connectors for the following conditions:

    • Backed-out terminals
    • Improper mating
    • Broken locks
    • Improperly formed or damaged terminals
    • Poor terminal to wiring connections or physical damage to the wiring harness.

       Important: Wheel speed sensor resistance increases with an increase in sensor temperature.

When measuring for a short to ground in a wheel speed sensor wiring circuit, manually switch J 39200 Digital Multimeter to the Meg-Ohms range. This will ensure a high resistance short to ground can be found. See the J 39200 owners manual.

Test Description

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

  1. The Diagnostic System Check must be the starting point for any ABS related diagnosis.

  2. Tests the wheel speed sensor internal resistance for proper values.

  3. Tests for wheel speed sensor circuits shorted together

  4. Tests for a short to ground in CKT 873.

  5. Tests for a short to ground in CKT 830.

  6. Tests for a short to voltage in CKT 873.

  7. Tests for a short to voltage in CKT 830.

  8. Tests for an open or high resistance in CKT 873.

  9. Tests for an open or a high resistance in CKT 830.

  10. Tests for poor connections at electrical connectors.

  11. Determines whether the condition is intermittent and not due to a faulty EBCM.

Step

Action

Value(s)

Yes

No

1

Was the Diagnostic System Check performed?

Go to Step 2

Go to Diagnostic System Check

2

  1. Remove the left front wheel.
  2. Disconnect the left front wheel speed sensor electrical connector.
  3. Use J 39200 DMM in order to measure the resistance between the left front wheel speed sensor connector terminals A and B (sensor side).

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

1120-2520 ohms

Go to Step 3

Go to Step 12

3

  1. Disconnect the Electronic Brake Control Module (EBCM) electrical connector.
  2. Use J 39200 DMM in order to measure the resistance between the left front wheel speed sensor connector terminals A and B (harness side).

Is the resistance equal to the value specified in the Value(s) column?

OL

(Infinite)

Go to Step 4

Go to Step 13

4

Use J 39200 DMM in order to measure the resistance between the left front wheel speed sensor connector terminal A (harness side) and ground.

Is the resistance equal to the value specified in the Value(s) column?

OL

(Infinite)

Go to Step 5

Go to Step 14

5

Use J 39200 DMM in order to measure the resistance between the left front wheel speed sensor connector terminal B (harness side) and ground.

Is the resistance equal to the value specified in the Value(s) column?

OL

(Infinite)

Go to Step 6

Go to Step 15

6

  1. Turn the ignition switch to the ON position.
  2. Use J 39200 DMM in order to measure the voltage between the left front wheel speed sensor connector terminal A (harness side) and ground.

Is the voltage within the range specified in the Value(s) column?

0-1 V

Go to Step 7

Go to Step 16

7

Use J 39200 DMM in order to measure the voltage between the left front wheel speed sensor connector terminal B (harness side) and ground.

Is the voltage within the range specified in the Value(s) column?

0-1 V

Go to Step 8

Go to Step 17

8

Use J 39200 DMM in order to measure the resistance between the left front wheel speed sensor connector terminal A (harness side) and the Electronic Brake Control Module (EBCM) electrical connector terminal 17 (harness side).

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

0-2 ohms

Go to Step 9

Go to Step 18

9

Use J 39200 DMM in order to measure the resistance between the left front wheel speed sensor connector terminal B (harness side) and the Electronic Brake Control Module (EBCM) electrical connector terminal 18 (harness side).

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

0-2 ohms

Go to Step 10

Go to Step 19

10

Inspect the Electronic Brake Control Module (EBCM) electrical connector and the left front wheel speed sensor connector for poor terminal contact, corrosion or damage. Repair as necessary.

Is the action complete?

--

Go to Step 11

--

11

  1. Turn the ignition switch to the LOCK position.
  2. Reconnect the left front wheel speed sensor electrical connector.
  3. Reconnect the Electronic Brake Control Module (EBCM) electrical connector.
  4. Turn the ignition switch to the ON position.
  5. Connect a scan tool to the Data Link Connector (DLC).
  6. Select Diagnostic Trouble Codes (DTC) on scan tool.
  7. Select DTC Information on the scan tool.
  8. Select Current DTC on the scan tool.

Is DTC C0035 set as a Current DTC?

--

Go to Step 21

Go to Step 20

12

Replace the left front wheel speed sensor. Refer to Wheel Speed Sensor Replacement .

Is the repair complete?

--

Go to Diagnostic System Check

--

13

Repair the short between CKT 830 and CKT 873. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Diagnostic System Check

--

14

Repair the short to ground in CKT 873. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Diagnostic System Check

--

15

Repair the short to ground in CKT 830. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Diagnostic System Check

--

16

Repair the short to voltage in CKT 873. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Diagnostic System Check

--

17

Repair the short to voltage in CKT 830. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Diagnostic System Check

--

18

Repair open or a high resistance in CKT 873. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Diagnostic System Check

--

19

Repair open or a high resistance in CKT 830. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Diagnostic System Check

--

20

A malfunction is not present at this time. Refer to Diagnostic Aids for additional information regarding this DTC.

Is the action complete?

--

Go to Diagnostic System Check

--

21

Test the electrical harness between the EBCM and the left front wheel speed sensor for the following conditions:

    • For a possible short to ground
    • For a short to voltage
    • For an open in CKT 830 or in CKT 873.
        Inspect the EBCM electrical connector for poor terminal contact. Repair the wiring as necessary. If the wiring is OK, replace the brake pressure modulator value assembly. Refer to Brake Pressure Modulator Valve Assembly Replacement .

Is the repair complete?

--

Go to Diagnostic System Check

--