Antilock Braking System (ABS)

DTC 31 & 35 Rear Wheel Speed Circuit Test:

Rear Wheel Speed Sensor Circuit Open Or Shorted:

CIRCUIT OPERATION
When each wheel turns, the wheel speed sensor creates a small AC voltage with a frequency proportional to wheel speed. This magnetically induced voltage is caused by a toothed sensor ring passing the wheel speed sensor's stationary pickup coil. Both sensors are part of the hub and bearing assembly.

The EBCM/EBTCM uses the wheel speed sensor signal to calculate vehicle reference speeds and individual wheel speed, acceleration and slip values. These values are used to determine when antilock control is required.

WHEEL SPEED SENSOR CABLES
In order to prevent electromagnetic interference from disturbing the wheel speed sensor signal, the cables from the EBCM/EBTCM to each wheel speed sensor are twisted in pairs a minimum of 6 to 9 turns per foot.

When servicing the sensor cables it is important to maintain the original cable's twists (6 to 9 turns per foot).

FAILURE CONDITIONS
The EBCM/EBTCM performs two basic checks on the wheel speed sensors: sensor continuity and sensor output. When the ignition is first turned to "RUN," the EBCM/EBTCM performs the wheel speed sensor continuity check.

Sensor Continuity Check
Any condition which would result in lack of continuity in the rear wheel speed sensor circuit could result in a DTC 31 or 35 being set. These conditions include an open, a short to ground, or a short between the two wheel speed sensor circuits in the wiring harness between the speed sensor and EBCM/EBTCM. Also an open or short to ground across the wheel speed sensor coil could trigger this DTC.