GM Service Manual Online
For 1990-2009 cars only

Circuit Description

As the wheel is rotated, the speed sensor produces an alternating current (AC) voltage that increases with wheel speed. The electronic brake control module (EBCM) uses the frequency of the AC signal to calculate wheel speed. The speed sensor is connected to the EBCM by a twisted pair of wires. Twisting reduces noise susceptibility that may cause a DTC to set.

Conditions for Setting the DTC

DTC C0035 can be set anytime the key is ON and the EBCM has detected an open, short to ground, or a short to battery on the right rear wheel speed circuit.

Action Taken When the DTC Sets

    • The solenoid relay opens, removing power from the pump motor and solenoids.
    • DTC C0035 is stored.
    • The antilock brake system (ABS) is disabled, ABS warning lamp turns ON.

Conditions for Clearing the DTC

    • If the conditions that set DTC C0035 are no longer present, the DTC may be cleared by using the proper scan tool.
    • The DTC that has not occurred in 100 drive cycles will be cleared from history data.

Diagnostic Aids

Thoroughly inspect the wiring and connectors when diagnosing intermittent DTCs. This will include the following:

    • Removal of the protective conduit and inspection to wiring for damage, shorts, and contamination
    • Inspection for improperly formed and/or damaged terminals
    • Inspecting terminal contact, retention force, by using a spare male/female terminal
    • Removal of the terminals from the connectors to inspect for proper terminal to wire crimp

If the drivers comments reflect that the ABS warning lamp is ON only during moist environmental changes, such as rain, snow, vehicle wash, etc., all wheel speed sensor circuitry should be thoroughly inspected for signs of water intrusion. If the DTC is not current, simulate the effects of water intrusion. Use the following procedure. Spray the suspected area with a 5 percent saltwater solution. Then test drive the vehicle over various road surfaces such as bumps, turns, etc. above 24 km/h (15 mph). If the DTC sets, replace the suspected harness and/or sensor.

When measuring wheel speed sensor resistance insure the vehicle is at room temperature, since resistance will increase with temperature.

Failure to perform the previous steps carefully and fully can result in misdiagnosis, unnecessary component replacement, and reoccurrence of DTC C0035.

Step

Action

Values

Yes

No

1

Did you perform the Diagnostic System Check-ABS?

--

Go to Step 2

Go to Diagnostic System Check - ABS

2

  1. Turn the ignition switch OFF.
  2. Inspect the right rear wheel speed sensor, jumper harness, and the toothed ring for physical damage.

Is any physical damage noted?

--

Go to Step 3

Go to Step 4

3

Repair the damage to the right rear wheel speed sensor, jumper harness, and/or toothed ring.

Did you complete the repair?

--

System OK

--

4

Test drive the vehicle at various speeds and over various road surfaces.

Did DTC C0035 reset?

--

Go to Step 6

Go to Step 5

5

DTC C0035 is intermittent. Refer to Diagnostic Aids.

Did you find and correct the condition?

--

System OK

--

6

  1. With the vehicle in park, turn the ignition switch OFF.
  2. Raise and suitably support the vehicle.
  3. Disconnect the right rear jumper harness from the right rear wheel speed sensor.
  4. Important: Resistance will vary with temperature.

  5. Connect an ohmmeter to terminals B and Aof the right rear wheel speed sensor.

Does the resistance measure within the specified range?

800-1600 ohms

Go to Step 8

Go to Step 7

7

Replace the right rear wheel speed sensor.

Did you complete the replacement?

--

System OK

--

8

  1. The right rear jumper harness is still disconnected from the speed sensor.
  2. Connect an ohmmeter to terminal B of the right rear wheel speed sensor and then to body ground.

Does the resistance measure OL, open circuit?

OL (Open Circuit)

Go to Step 9

Go to Step 7

9

  1. Disconnect the electronic brake control module (EBCM) harness from the EBCM.
  2. Disconnect the right rear jumper harness from the ABS body harness.
  3. Connect an ohmmeter to EBCM harness terminal A05 and then the ABS body harness terminal B.

Does the resistance measure less than the specified value?

2 ohms

Go to Step 11

Go to Step 10

10

Repair the open or high resistance between terminals A05 and B.

Did you complete the repair?

--

System OK

--

11

  1. Verify the EBCM harness is still disconnected from the EBCM.
  2. Verify the right rear jumper harness is still disconnected from the ABS body harness.
  3. Connect an ohmmeter to EBCM harness terminal A06 and then to ABS body harness terminal A.

Does the resistance measure less than the specified value?

2 ohms

Go to Step 13

Go to Step 12

12

Repair the open or high resistance between terminals A06 and A.

Did you complete the repair?

--

System OK

--

13

  1. Verify the EBCM harness is still disconnected from the EBCM.
  2. Verify the right rear jumper harness is still disconnected from the ABS body harness.
  3. Connect a voltmeter to EBCM harness terminal A05 and then to body ground.

Does the voltage measure less than the specified value?

1 V

Go to Step 15

Go to Step 14

14

Repair the short to voltage between terminals A05 and 2.

Did you complete the repair?

--

System OK

--

15

  1. Verify the EBCM harness is still disconnected from the EBCM.
  2. Verify the right rear jumper harness is still disconnected from the ABS body harness.
  3. Connect a voltmeter to EBCM harness terminal A05 and then to body ground.

Does the voltage measure less than the specified value?

1 V

Go to Step 17

Go to Step 16

16

Repair the short to voltage between terminals A05 and B.

Did you complete the repair?

--

System OK

--

17

  1. Verify the EBCM harness is still disconnected from the EBCM.
  2. Verify the right rear jumper harness is still disconnected from the ABS body harness.
  3. Connect an ohmmeter to EBCM harness terminal A6 and then to body ground.

Does the resistance measure OL, open circuit?

--

Go to Step 19

Go to Step 18

18

Repair the short to ground between terminals A6 and 2.

Did you complete the repair?

--

System OK

--

19

  1. Verify the EBCM harness is still disconnected from the EBCM.
  2. Verify the right rear jumper harness is still disconnected from the ABS body harness.
  3. Connect an ohmmeter to EBCM harness terminal A05 and then to body ground.
  4. Verify the left front jumper harness is still disconnected from the ABS body harness.

Does the resistance measure OL, open circuit?

--

Go to Step 21

Go to Step 20

20

Repair the short to ground between terminals A05 and B.

Did you complete the repair?

--

System OK

--

21

  1. Verify the EBCM harness is still disconnected from the EBCM.
  2. Verify the right rear jumper harness is still disconnected from the ABS body harness.
  3. Connect an ohmmeter to EBCM harness terminal A06 and A05.

Does the resistance measure OL, open circuit?

--

Go to Step 23

Go to Step 22

22

Repair the short between the 2 circuits.

Did you complete the repair?

--

System OK

--

23

  1. Replace the right rear wheel speed sensor jumper harness.
  2. Test drive the vehicle at various speeds and various road surfaces.

Did DTC C0035 reset?

--

Go to Step 24

System OK

24

Replace the EBCM.

Did you complete the replacement?

--

System OK

--