Antilock Braking System (ABS)

Code 35: Rear Wheel Speed Sensor Circuit Fault (Part 1 Of 2).:

Code 35: Rear Wheel Speed Sensor Circuit Fault (Part 2 Of 2).:

Front Wheel Speed Sensor Circuit Fault:

CIRCUIT DESCRIPTION
The toothed wheel (mounted to the differential pinion gear) generates a voltage pulse as it moves past the sensor; each tooth-gap-tooth series on the wheel generates a pulse. The frequency of these pulses is used by the EBCM to determine wheel speed. The amplitude of the voltage generated in each pulse depends on the air gap between the sensor and the toothed wheel, and on wheel speed.

DTC 35 WILL SET WHEN
- There is a short to voltage or ground in CKT 883 or 882.
- There is a malfunctioning speed sensor.
- It is possible that driving with a compact spare at speeds above 40 km/h (24 mph) may cause this fault

The test for this malfunction occurs when the vehicle is in motion; it will not set with the ignition in "RUN" and the vehicle at rest.

ACTION TAKEN
The "ABS" lamp will be "ON." ABS is disabled.

DTC CHART TEST DESCRIPTION
Number(s) below refer to circled number(s) on the diagnostic chart.
1. Checks for proper resistance in the sensor itself.
2. Checks for a short to voltage in either of the speed sensor circuit wires.
3. Checks for a short between the speed sensor circuit wires.
4. Checks for a short to ground in the speed sensor input circuit wire. The ground may be either a "hard" short to ground, or a resistive (partial) short. A short with a resistance less than 2 megohms, though not a "hard" short, can still cause DTC 35 to set.
5. Checks if the DTC resets during a road test. If so, since tests 1-4 have validated that all of the circuitry and components are good, intermittent malfunctions are suspected.
6. Checks wiring and connectors for intermittents.
7. Checks for sensor mounting and for damage to the toothed wheel which may be causing the malfunction.
8. Replace the speed sensor as it is likely the cause of a DTC reset experienced during the road test, since other portions of the circuit have checked out OK.

DIAGNOSTIC AIDS
Be sure the speed sensor wiring is properly routed and retained. This will help prevent false signals due to electrical noise being picked up by the wiring.
It is very important that a thorough inspection of the wiring and connectors be performed. Failure to carefully and fully inspect wiring and connectors may result in misdiagnosis, causing part replacement with reappearance of the malfunction.
The Tech 1 can also be used to monitor the wheel speeds during a road test. Watch the wheel speeds being displayed on the Tech 1 to see if any of the readings are unusual, such as one sensor varying in speed from the other three, a signal going intermittently high or low, etc. If this does not identify the intermittent, wet the speed sensor harness on the underside of the vehicle and road test monitoring wheel speeds with the Tech 1.