C1235
DTC C1235: Right Rear Wheel Speed Sensor Circuit Open Or Shorted (Part 1 Of 3):
DTC C1235: Right Rear Wheel Speed Sensor Circuit Open Or Shorted (Part 2 Of 3):
DTC C1235: Right Rear Wheel Speed Sensor Circuit Open Or Shorted (Part 3 Of 3):
DTC C1235 Schematic:
Circuit Description
As a toothed ring passes by the wheel speed sensor, changes in the electromagnetic field cause the wheel speed sensor to produce a small AC voltage signal whose frequency is proportional to wheel speed.
Conditions for Setting the DTC
^ This DTC will set when the following conditions are met:
^ The Electronic Brake Control Module (EBCM) detects open, short to voltage, or short to ground in CKT 882A/B/C and/or CKT 883A/B/C.
^ DTC can be set anytime.
Action Taken When the DTC Sets
A malfunction DTC is stored, the amber ABS indicator lamp is turned ON and ABS is disabled.
Conditions for Clearing the DTC
^ Conditions for the malfunction are no longer present and the Tech 2 scan tool Clear DTC Information function is used.
^ One hundred drive cycles have passed with no malfunctions detected.
Diagnostic Aids
The following list contains items that need to be inspected when diagnosing this system:
^ Faulty electrical circuits (open/high resistance or short to battery voltage or ground) between the LF wheel speed sensor and the EBCM.
^ Faulty wheel speed sensor (high resistance).
An intermittent malfunction is most likely caused by a poor connection, rubbed through wire insulation, or a wire that is broken inside the insulation.
The frequency of the malfunction can be checked by using the Enhanced Diagnostic function of the Tech 2 scan tool, as described in Enhanced Diagnostics.
If the customer's comments reflect that the ABS indicator lamp is ON only during humid conditions (rain, snow, vehicle wash) all wheel speed sensor circuitry should be thoroughly inspected for signs of water intrusion. Use the following procedure. Spray down the suspected area with 5% salt water solution (two teaspoons of salt to 12 ounces of water). Drive vehicle above 24 km/h (15 mph) for at least 30 seconds. If the DTC returns immediately, replace suspected harness.
Any circuitry that is suspected of causing the intermittent complaint should be thoroughly checked for 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: Resistance of the wheel speed sensor will increase with an increase in sensor temperature.
When measuring for a short to ground in a wheel speed sensor wiring circuit, manually switch the J 39200 (Digital Multimeter) to the Meg-Ohms range. This will ensure a high resistance short to ground can be found. See J 39200 owners manual. When replacing a wheel speed sensor, inspect the sensor terminals and jumper harness connector for corrosion and/or water intrusion. If evidence of corrosion or water intrusion exists, replace both the wheel speed sensor and the jumper harness.
Test Description
The numbers below refer to steps on the diagnostic table.
2. Checks wheel speed sensor resistance.
3. Checks for CKT 882A/B/C and 883A/B/C shorted together.
4. Checks for short to ground in CKT 882A/B/C.
5. Checks for short to ground in CKT 883A/B/C.
6. Checks for short to voltage in CKT 883AIBiC.
7. Checks for short to voltage in CKT 882A/B/C.
8. Checks for open in CKT 882A/B/C.
9. Checks for open in CKT 883A/B/C.
10. Checks for poor terminal contact.
11. Checks if this DTC resets after two key-on cycles.