DTC 37

DTC 22, 23, 26, 27, 32, 33, 36 & 37 Wheel Speed Signal Erratic Or Missing (part 1 Of 2):

DTC 22, 23, 26, 27, 32, 33, 36 & 37 Wheel Speed Signal Erratic Or Missing (part 2 Of 2):

Wheel Speed Signal Erratic Or Missing:

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. The toothed ring sensor is mounted on the drive axle in the front, and in the hub/bearing assembly in the rear,

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 anti lock control is required. Vehicles equipped with traction control also use front wheel speed sensor signals to determine when traction 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 cables' twist (6 to 9 turns per foot).

FAILURE CONDITIONS
DTC 22, DTC 26, DTC 33 or DTC 36 sets when the EBCM/EBTCM detects electromagnetic interference (noise) in a wheel speed sensor signal. Possible interference sources include accessory motors, wiper motors, ignition circuits and any add-on or "After Market" equipment.

DTC 22, DTC 26, DTC 32 or DTC 36 also sets when the EBCM/EBTCM determines a wheel speed signal is erratic. A wheel speed signal indicating that a wheel is accelerating or decelerating faster than physically possible is an example of an erratic signal. An intermittent open or short to ground in a wheel speed sensor could also cause the EBCM/EBTCM to set a DTC.

DTC 23, DTC 27, DTC 33, or DTC 37 sets when the EBCM/EBTCM does not see any wheel speed sensor signal, but determines continuity exists in the circuit. This is cause by a dislodged wheel speed sensor, missing toothed sensor ring (front) or defective hub and bearing assembly (rear).