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For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2000 🢒 Metro 🢒 Brakes 🢒 Antilock Brake System 🢒 DTC C1235 RR Wheel Speed Circuit Open or Shorted

Object Number: 234277 Size: SF
ABS Components
Cell 44: Wheel Speed Sensors and Motor Pack
Handling ESD Sensitive Parts Notice

Circuit Description

As a toothed ring passes by the wheel speed sensor, changes in the electromagnetic field cause the wheel speed sensor to produce an AC voltage signal. The frequency of the AC voltage signal is proportional to the wheel speed. The amplitude of the AC voltage signal is directly related to wheel speed and the proximity of the wheel speed sensor to the toothed ring. The proximity of the wheel speed sensor to the toothed ring is also referred to as the air gap.

Conditions for Setting the DTC
    • DTC C1235 can set anytime after initialization.
    • A malfunction exists if either of the right rear wheel speed sensor circuits are open or shorted to voltage or ground.

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.
    • 100 drive cycles pass with no DTCs detected. A drive cycle consists of starting the vehicle, driving the vehicle over 16 km/h (10 mph), stopping and then turning the ignition OFF.

Diagnostic Aids

The following conditions may cause a malfunction:

    • A poor connection
    • Rubbed-through wire insulation
    • A broken wire inside the insulation
    • Faulty electrical circuits (open/high resistance, short to voltage or ground) between the RR wheel speed sensor and the EBCM
    • Malfunctioning wheel speed sensor (high resistance)

Use the enhanced diagnostic function of the Scan Tool in order to measure the frequency of the malfunction.

If the customer's comments reflect that the amber ABS warning indicator is ON only during moist environmental changes (rain, snow, vehicle wash), inspect all the wheel speed sensor circuitry for signs of water intrusion. If the DTC is not current, clear all DTCs and simulate the effects of water intrusion by using the following procedure:

  1. Spray the suspected area with a five percent saltwater solution.

    2. Add two teaspoons of salt to twelve ounces of water to make a five percent saltwater solution.

  2. Test drive the vehicle over various road surfaces (bumps, turns, etc.) above 24 km/h (15 mph) for at least 30 seconds.
  3. If the DTC returns, replace the suspected harness.

Thoroughly inspect any circuitry that may be causing 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

Resistance of the wheel speed sensor will increase with an increase in sensor temperature.

Use the following procedure when replacing a wheel speed sensor or harness:

  1. Inspect the wheel speed sensor terminals and harness connector for corrosion and/or water intrusion.
  2. Replace the wheel speed sensor and jumper harness if evidence of corrosion or water intrusion exists.

Test Description

  1. This test checks the wheel speed sensor circuitry for the proper resistance values at the EBCM.

    2.

  2. This test checks for a short to ground in the wheel speed sensor circuit.

    3.

  3. This test checks for a short to voltage in either the high or the low wheel speed sensor signal circuits.

    4.

  4. This test checks the wheel speed sensor for the proper resistance value.

    5.

  5. This test checks for an open or high resistance in the wheel speed sensor signal high circuit.

    6.

  6. This test checks for an open or high resistance in the wheel speed sensor signal low circuit.

    7.

  7. This test checks for a short to ground in the wheel speed sensor signal high circuit.

    8.

  8. This test checks for a short to ground in the wheel speed sensor signal low circuit.

    9.

  9. This test determines if the wheel speed sensor signal high circuit is shorted to voltage.

    10.

  10. This test determines if the wheel speed sensor signal low circuit is shorted to voltage.

    11.

  11. This test determines if the malfunction is caused by the EBCM.

Step

Action

Value(s)

Yes

No

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

Important: Difficulty may occur when trying to locate intermittent malfunctions in the wheel speed sensor circuit.

Do not disturb any of the electrical connections. Change the electrical connections only when instructed to do so by a step in the diagnostic table.

Changing the electrical connections at the correct time will ensure that an intermittent electrical connection will not be corrected until the source of the malfunction is found.

1

Was A Diagnostic System Check-ABS performed?

--

Go to Step 2

Go to Diagnostic System Check - ABS

2

  1. Turn the ignition switch to the OFF position.
  2. Disconnect the EBCM harness connector.
  3. Use the J 39200 in order to measure the resistance between the EBCM harness connector terminal A2 and the EBCM harness connector terminal B1.

Is the resistance within the specified range?

920-1220 ohms

Go to Step 3

Go to Step 5

3

Use the J 39200 in order to measure the resistance between the EBCM harness connector terminal B1 and ground.

Is the resistance within the specified range?

OL (Infinite)

Go to Step 4

Go to Step 8

4

  1. Turn the ignition switch to the ON position.

    2. Do not start the engine.

  2. Use the J 39200 in order to measure the voltage between the EBCM harness connector terminal B1 and ground.

Is the voltage within the specified range?

0-1 V

Go to Step 12

Go to Step 10

5

  1. Disconnect the wheel speed sensor connector.
  2. Use the J 39200 in order to measure the resistance between the wheel speed sensor terminals A and B.

Is the resistance within the specified range?

920-1220 ohms

Go to Step 6

Go to Step 14

6

Use the J 39200 in order to measure the resistance between the EBCM connector C1 terminal A2 and the wheel speed sensor connector terminal A.

Is the resistance within the specified range?

0-2 ohms

Go to Step 7

Go to Step 15

7

Use the J 39200 in order to measure the resistance between the EBCM connector C1 terminal B1 and the wheel speed sensor connector terminal B.

Is the resistance within the specified range?

0-2 ohms

Go to Testing for Electrical Intermittents in Wiring Systems

Go to Step 16

8

  1. Disconnect the wheel speed sensor connector.
  2. Use the J 39200 in order to measure the resistance between the wheel speed sensor connector terminal A and ground.

Is the resistance within the specified range?

OL (Infinite)

Go to Step 9

Go to Step 17

9

Use the J 39200 in order to measure the resistance between the wheel speed sensor connector terminal B and ground.

Is the resistance within the specified range?

OL (Infinite)

Go to Testing for Electrical Intermittents in Wiring Systems

Go to Step 18

10

  1. Turn the ignition switch to the ON position.
  2. Disconnect the wheel speed sensor connector.
  3. Use the J 39200 in order to measure the voltage between the wheel speed sensor connector terminal A and ground.

Is the voltage within the specified range?

0-1 V

Go to Step 11

Go to Step 19

11

Use the J 39200 in order to measure the voltage between the wheel speed sensor connector terminal B and ground.

Is the voltage within the specified range?

0-1 V

Go to Testing for Electrical Intermittents in Wiring Systems

Go to Step 20

12
  1. Turn the ignition switch to the OFF position.
  2. Inspect the following terminals:
    3. • The EBCM connector terminal A2
    • The EBCM connector terminal B1
    • The remaining terminals of the EBCM connector.
  3. Inspect the above terminals for the following conditions:
    4. • Terminal damage
    • Poor terminal contact
    • Terminal corrosion
    • Damage, terminal corrosion, and poor terminal contact may cause an open circuit, a short to voltage, or a short to ground.

Are there signs of poor terminal contact, terminal corrosion, or damaged terminals?

--

Go to Step 21

Go to Step 13

13

  1. Reconnect the EBCM connector.
  2. Reconnect the wheel speed sensor harness connector.
  3. Install a Scan Tool .
  4. Test drive the vehicle at a speed above 24 km/h (15 mph) for at least 30 seconds.
  5. Use the Scan Tool in order to read the DTCs.

Does DTC C1235 set as a current DTC?

--

Go to Step 22

Go to Step 23

14

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

Is the repair complete?

--

Go to Diagnostic System Check - ABS

--

15
  1. Repair the open or high resistance in the BLK or YEL wire between the right rear WSS and the EBCM. Refer to Wiring Repairs in Wiring Systems.
  2. If the open or high resistance is found in the right rear wheel speed sensor jumper harness, replace the right rear wheel speed sensor jumper harness. Refer to Wheel Speed Sensor Jumper Harness Replacement .

Is the repair complete?

--

Go to Diagnostic System Check - ABS

--

16
  1. Repair the open or high resistance in the WHT or YEL/BLK wire between the right rear WSS and the EBCM. Refer to Wiring Repairs in Wiring Systems.
  2. If the open or high resistance is found in the right rear wheel speed sensor jumper harness, replace the right rear wheel speed sensor jumper harness. Refer to Wheel Speed Sensor Jumper Harness Replacement .

Is the repair complete?

--

Go to Diagnostic System Check - ABS

--

17
  1. Repair the short to ground in the YEL or BLK wire between the right rear WSS and the EBCM. Refer to Wiring Repairs in Wiring Systems.
  2. If the short to ground is found in the right rear wheel speed sensor jumper harness, replace the right rear wheel speed sensor jumper harness. Refer to Wheel Speed Sensor Jumper Harness Replacement .

Is the repair complete?

--

Go to Diagnostic System Check - ABS

--

18
  1. Repair the short to ground in the WHT or YEL/BLK wire between the right rear WSS and the EBCM. Refer to Wiring Repairs in Wiring Systems.
  2. If the short to ground is found in the right rear wheel speed sensor jumper harness, replace the right rear wheel speed sensor jumper harness. Refer to Wheel Speed Sensor Jumper Harness Replacement .

Is the repair complete?

--

Go to Diagnostic System Check - ABS

--

19
  1. Repair the short to voltage in the YEL or BLK wires between the right rear WSS and the EBCM. Refer to Wiring Repairs in Wiring Systems.
  2. If the short to voltage is found in the right rear wheel speed sensor jumper harness, replace the right rear wheel speed sensor jumper harness. Refer to Wheel Speed Sensor Jumper Harness Replacement .

Is the repair complete?

--

Go to Diagnostic System Check - ABS

--

20
  1. Repair the short to voltage in the WHT or YEL/BLK wire between the right rear WSS and the EBCM. Refer to Wiring Repairs in Wiring Systems.
  2. If the short to voltage is found in the right rear wheel speed sensor jumper harness, replace the right rear wheel speed sensor jumper harness. Refer to Wheel Speed Sensor Jumper Harness Replacement .

Is the repair complete?

--

Go to Diagnostic System Check - ABS

--

21

Replace all of the terminals and the connectors that exhibit signs of poor terminal contact, corrosion, or damaged terminals. Refer to Connector Repairs in Wiring Systems.

Is the repair complete?

--

Go to Diagnostic System Check - ABS

--

22

Replace the EBCM. Refer to Electronic Brake Control Module Replacement .

Is the repair complete?

--

Go to Diagnostic System Check - ABS

--

23

The malfunction is intermittent or not present at this time.

Inspect all of the connectors and the harnesses for damage that could cause the following conditions:

    • An open or a high resistance
    • A short to ground
    • A short to voltage

The sensor harness must be replaced if the sensor harness is damaged.

Refer to Diagnostic Aids for more information.

Is the action complete?

--

System OK

--