DTC C1233, C1234, C1235, C1236 [YF (2.0L Zetec), AJ (3.0L Duratec)]

DTC	C1233, C1234, C1235, C1236	ABS sensor rotor
MALFUNCTION	• C1233 - ABS wheel-speed sensor (LF) output malfunction • C1234 - ABS wheel-speed sensor (RF) output malfunction • C1235 - ABS wheel-speed sensor (RR) output malfunction • C1236 - ABS wheel-speed sensor (LR) output malfunction


STEP	INSPECTION		ACTION
1	INSPECT FOR DTC • Turn the ignition switch off. • Connect the WDS or the equivalent. • Turn the ignition switch to the ON position. • Verify if any DTCs are displayed. • Is DTC C1145, C1155, C1165, or C1175 displayed?	Yes	• Go to the DTC C1145, C1155, C1165, or C1175 diagnostic procedure. (See DTC C1145, C1155, C1165, C1175 [YF (2.0L Zetec), AJ (3.0L Duratec)].)
1		No	• Go to the next step.
2	INSPECT ABS WHEEL-SPEED SENSOR PID • Turn the ignition switch to the ON position. • Monitor the ABS wheel-speed sensor PIDs LF_WSPD, RF_WSPD, LR _WSPD and RR _WSPD while driving the vehicle at a constant speed. • Are the ABS wheel-speed sensor PIDs displayed?	Yes	• Clear the DTC from the memory. Drive the vehicle. Read DTCs again. If DTC C1233, C1234, C1235, or C1236 is displayed, replace the ABS CM. (See ABS CM REMOVAL/INSTALLATION.)
2		No	• Go to the next step.
3	INSPECT ABS WHEEL-SPEED SENSOR FOR DAMAGE AND LOOSENESS • Turn the ignition switch off. • Lift up the vehicle. • Inspect the ABS wheel-speed sensor mounting for looseness. If the ABS wheel-speed sensor is suspected, inspect the sensor for corrosion on the rear axle housing boss. Clean if necessary. Caution • Inspect the ABS wheel-speed sensor wiring harness carefully in a well-lit area. Failure to verify damage in the ABS wheel-speed sensor wiring harness can lead to unnecessary replacement of the component parts. • Is the ABS wheel-speed sensor normal?	Yes	• Go to the next step.
3		No	• If the ABS wheel-speed sensor mounting is loose or corroded, remove the ABS-wheel-speed sensor, plug the opening, and thoroughly clean the mounting surfaces. Apply High Temperature 4x4 Front Axle and Wheel Bearing Grease E8TZ-19590-A or equivalent meeting the specification ESA-M1C198-A to the ABS wheel-speed sensor. • If the ABS wheel-speed sensor is damaged, replace the ABS wheel-speed sensor and repeat the self-test. (See FRONT ABS WHEEL-SPEED SENSOR REMOVAL/INSTALLATION.) (See REAR ABS WHEEL-SPEED SENSOR REMOVAL/INSTALLATION.)
4	INSPECT ABS SENSOR ROTOR • Remove the ABS wheel-speed sensor. • Inspect the ABS wheel-speed sensor for damage or missing teeth. Rotate the wheel to verify that no teeth are missing. Caution • Inspect the ABS wheel-speed sensor rotor carefully in a well-lit area. Failure to verify damage in the ABS wheel-speed sensor rotor can lead to unnecessary replacement of the component parts. • Is the ABS sensor rotor normal?	Yes	• Go to the next step.
4		No	• Replace the ABS sensor rotor. Clear the DTC from the memory and repeat the self-test.