C1221

DTC C1221 LF Wheel Speed Sensor Input = 0:

Wheel Speed Sensor Schematic:

CIRCUIT DESCRIPTION
The speed sensor used on this vehicle is a single point magnetic pickup. This sensor produces an AC signal that the EBCM/EBTCM uses the frequency from to calculate the wheel speed.

CONDITION FOR SETTING THE DTC
- The DTC will set if the LF wheel speed - 0 and the other WSS are greater than 8 Km/h (5 mph) for 2.5 seconds.

ACTION TAKEN WHEN THE DTC SETS
- A malfunction DTC is stored, ABS/TCS is disabled and the "ABS" and "TRACTION OFF" Indicator lamps are turned "ON."

CONDITIONS FOR CLEARING DTC
- Condition for DTC is no longer present and scan tool clear DTC function is used.
- 50 ignition cycles have passed with no DTC(s) detected.

DIAGNOSTIC AIDS
- 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.
- An intermittent malfunction can be caused by poor connections, broken insulation, or a wire that is broken inside the insulation.

TEST DESCRIPTION
The numbers below refer to step numbers on the diagnostic table.
3. Checks the resistance of the WSS.
5. Checks if the WSS CKTs are shorted together.