ABS - Integrated Chassis Control

DTC C1225: LF Excessive Wheel Speed Variation (Part 1 Of 2):

DTC C1225: LF Excessive Wheel Speed Variation (Part 2 Of 2):

DTC C1225 Schematic:

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

CONDITION FOR SETTING THE DTC
The DTC can be set anytime the brake is not depressed and no wheel speed sensor hardware DTCs are present, and the EBTCM sees a wheel speed variation of more than 14 Km/h (9 mph) for 2.5 seconds.

ACTION TAKEN WHEN THE DTC SETS
A malfunction DTC is stored, ABS/TCS/ICCS is disabled and the ABS and TRACTION CONTROL Indicator lamps are turned ON. Vehicles with ICCS2 will display the STABILITY REDUCED message on the DIC.

CONDITIONS FOR CLEARING THE DTC
Condition for DTC is no longer present and scan tool clear DTC function is used. Fifty start cycles have passed with no DTCs 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. Use these tests: Salt Water Spray test for water intrusion and Electromagnetic Interference test for proper wire routing

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