C1226

CIRCUIT DESCRIPTION
The wheel speed sensor creates an AC voltage as each wheel turns. The frequency of this voltage is proportional to the wheel speed.

The voltage is magnetically induced. It is caused by a toothed sensor ring (mounted on the drive axle) which passes the stationary pickup coil of the wheel speed sensor.

The EBCM/EBTCM uses the wheel speed sensor signal in order to calculate the following values:
^ The vehicle reference speeds
^ The speed of each wheel
^ The acceleration
^ The slip values

Use these values in order to determine when antilock or traction control (when equipped) is required.

CONDITIONS FOR SETTING THE DTC
The DTC C1226 sets when the EBCM/EBTCM detects electromagnetic interference (noise) in a wheel speed sensor signal.

The following components may be sources of interference:
^ The accessory motors
^ The wiper motors
^ The ignition circuits
^ Any add-on or after market equipment

The DTC C1226 also sets when the EBCM/EBTCM determines that a wheel speed signal is erratic. (An example of an erratic signal is a signal which indicates that a wheel is accelerating faster than physically possible.)

An intermittent or a short to ground in a wheel speed sensor may also cause the EBCM/EBTCM in order to set a DTC.

ACTION TAKEN WITH THE DTC SETS
The following actions will be taken when the DTC sets:
^ A malfunction DTC is stored
^ The ABS is disabled
^ The ANTILOCK indicator lamp is turned ON

CONDITIONS FOR CLEARING THE DTC
The DTC will be cleared under following conditions:
^ Conditions for the malfunction are no longer present. Use the scan tool clear DTCs function.
^ 100 ignition switch key cycles have passed with no malfunctions detected

DIAGNOSTIC AIDS
One of the following conditions may cause an intermittent malfunction:
^ A poor connection
^ A rubbed through wire insulation
^ A wire that is broken inside the insulation

Inspect any suspect circuitry 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

TEST DESCRIPTION
The numbers below refer to step numbers on the diagnostic table:
4. This step ensures that the sensor is capable of putting out the necessary voltage to the EBCM/EBTCM.






DTC C1226 LF WHEEL SPEED SENSOR SIGNAL INTERMITTENT