Pinpoint Test 4: DTCs C1233 (LF), C1234 (RF), C1235 (RR) Or C1236 (LR) - Wheel Speed Sensor Input Signal Missing

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PINPOINT TEST 4: DTCs C1233 (LF), C1234 (RF), C1235 (RR) OR C1236 (LR) - WHEEL SPEED SENSOR INPUT SIGNAL MISSING

Normal Operation

The wheel speed sensor and sensor ring generate a square wave signal to the ABS module that is proportional to wheel speed. The ABS module compares wheel speed inputs from all wheel speed sensors to determine an impending wheel lockup. Incorrect tire size can set these DTCs as well.Voltage and ground signals are supplied to the wheel speed sensors from the ABS module. A difference in wheel speeds possibly caused by damaged wheel speed sensor rings, mismatched wheel sizes, driving on flat tires, an excessive wheel speed sensor air gap or a damaged tone ring will cause DTC C1233, C1234, C1235 or C1236 to set. Also an open or a short to voltage or ground in the sensor circuits will cause the appropriate DTC to set.

- DTC C1233 (Wheel Speed LF Input Signal Missing) - When the vehicle speed exceeds 15 km/h (9 mph), if the ABS module does not receive a signal from the LF wheel speed sensor, DTC C1233 will be set.
- DTC C1234 (Wheel Speed RF Input Signal Missing) - When the vehicle speed exceeds 15 km/h (9 mph), if the ABS module does not receive a signal from the RF wheel speed sensor, DTC C1234 will be set.
- DTC C1235 (Wheel Speed RR Input Signal Missing) - When the vehicle speed exceeds 15 km/h (9 mph), if the ABS module does not receive a signal from the RR wheel speed sensor, DTC C1235 will be set.
- DTC C1236 (Wheel Speed LR Input Signal Missing) - When the vehicle speed exceeds 15 km/h (9 mph), if the ABS module does not receive a signal from the LR wheel speed sensor, DTC C1236 will be set.

Possible Causes
- Wiring, terminals or connectors
- Mismatched tire sizes
- Wheel speed sensor tone ring
- Wheel speed sensor
- Wheel bearing
- ABS module

Diagnostic Procedure

CAUTION:Use the flex probe kit for all test connections to prevent damage to the wiring terminals. Do not use standard multi-meter probes.

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