Possible Causes

Wheel speed sensor ring
Wheel speed sensor
ABS module

PINPOINT TEST 9 CHART - CHECK FOR CORRECT ANTI-LOCK BRAKE SYSTEM MODULE OPERATION

PINPOINT TEST 9		CHECK FOR CORRECT ANTI-LOCK BRAKE SYSTEM (ABS) MODULE OPERATION
STEP	INSPECTION		ACTION
1	CHECK ALL WHEEL SPEED SENSORS FOR DAMAGE AND LOOSENESS NOTE: If DTCs C1148, C1158, C1229, C1233, C1234 and C1237 were originally retrieved and cleared, CARRY OUT the following pinpoint test. NOTE: Any time a wheel speed sensor is removed, thoroughly clean the mounting surfaces. On front wheel speed sensors, apply grease. With the vehicle in NEUTRAL, position it on a hoist. See LIFTING . CAUTION: Examine the wheel speed sensor wire carefully with good light. Failure to verify damage inn the wheel speed sensor wire can lead to unnecessary installation of a new component. Inspect the wheel speed sensor mounting for looseness. If the wheel speed sensor is suspected, inspect the sensor for corrosion on the rear axle housing boss or on the front wheel speed sensor mounting flange. Clean as necessary. Is the wheel speed sensor OK?	Yes	Go to next step.
1		No	If the wheel speed sensor mounting is loose or corroded, remove the wheel speed sensor, plug the opening and thoroughly clean the mounting surfaces. Clear the DTCS. Repeat the self-test. If the wheel speed sensor is damaged, install a new sensor. For the front wheel speed sensor (4WD), see WHEEL SPEED SENSOR - FRONT, 4WD . Clear the DTCs. Repeat the self-test. For the front wheel speed sensor (2WD), see WHEEL SPEED SENSOR - FRONT, 2WD . Clear the DTCs. Repeat the self-test. For the rear sensor, see WHEEL SPEED SENSOR - REAR . Clear the DTCs. Repeat the self-test.
2	CHECK ALL WHEEL SPEED SENSOR RINGS FOR DAMAGE NOTE: Any time a wheel speed sensor is removed, thoroughly clean the mounting surfaces. On front wheel speed sensors, apply grease. Remove the wheel speed sensor. CAUTION: Examine the wheel speed sensor wire carefully with good light. Failure to verify damage in the wheel speed sensor wire can lead to unnecessary installation of a new component. Inspect the wheel speed sensor ring for damaged or missing teeth. Rotate the wheel to verify that no teeth are missing. Is the wheel speed sensor ring OK?	Yes	Go to next step.
2		No	Install a new wheel speed sensor ring. For the front wheel speed sensor ring (4WD), install a new front wheel hub. See WHEEL HUB . Clear the DTCs. Repeat the self-test with the brake pedal not applied. For the front wheel speed sensor ring (2WD), install a new front brake disc. See BRAKE DISC . Clear the DTCs. Repeat the self-test with the brake pedal not applied. For the rear wheel speed sensor ring, see WHEEL SPEED SENSOR - REAR . Clear the DTCs. Repeat the self-test with the brake pedal not applied.
3	CHECK FOR CORRECT ABS MODULE OPERATION Disconnect all ABS connectors. Check for: corrosion. pushed-out pins. spread terminals. Connect all ABS connectors and make sure they seat correctly. Operate the system and verify the concern is still present. Is the concern still present?	Yes	See ANTI-LOCK BRAKE SYSTEM (ABS) MODULE DIAGNOSTIC TROUBLE CODE (DTC) INDEX to continue diagnosis of the DTCs.
3		No	The system is operating correctly at this time. Concern may have been caused by a loose or corroded connector. Clear the DTCs. Repeat the self-test with the brake pedal not applied.