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Test Ll: Left Front Speed Sensor Coherency Fault

NOTE: This test is associated with the following DTCs: C1158, C1233 and C1258.

  1. Code C1158, C1233 Or C1258

    - Turn ignition switch to OFF position. Install Breakout Box (014-00322) with proper overlay. Raise and support vehicle. Check front wheel bearing adjustment. Check sensor tone ring for damage. Check sensor mounting for looseness. Repair as necessary. If components are okay, go to next step.

  2. Check Speed Sensor Output

    - Remove left front tire. Compress caliper slightly to ensure wheel spins freely. Install left front tire. On 2WD models, spin left front wheel at about one revolution per second. On 4WD models, shift transfer case into 4WD low mode. Start engine and allow wheels to rotate at engine idle speed. On all vehicles, set Rotunda Meter (105-R0053) or equivalent, to frequency counter (Hz) setting. Measure and record frequency between breakout box pins No. 24 and 25. Change meter to A/C mV setting. Measure and record voltage output between breakout box pins No. 24 and 25. Ensure both measurements are recorded at same wheel speed. Determine sensor output in mV/Hz, by dividing A/C voltage reading by frequency reading. If sensor output is more than 3.0 mV/Hz on AWD/4WD, or more than 5.0 mV/Hz for 2WD models, output at ABS control module indicates air gap and sensor signal are okay. Go to step 6). If sensor output is less than specified, sensor output at ABS control module is insufficient. Go to next step.

  3. Check Output At Speed Sensor

    - Disconnect sensor connector. Repeat step 2), but measure and record frequency between 2 pins of sensor connector. Change meter to A/C mV setting. Measure and record voltage output between 2 pins of sensor connector. Ensure both readings are measured at same wheel speed. Determine sensor output in mV/Hz, by dividing A/C voltage reading by frequency reading. If sensor output is more than 3.0 mV/Hz on AWD/4WD, or more than 5.0 mV/Hz for 2WD models, output indicates air gap and sensor signal are okay. Go to step 6). If sensor output is less than specified, go to next step (except AWD/4WD) or replace wheel speed sensor (AWD/4WD).

  4. Check Speed Sensor Air Gap

    - Ensure sensor mounting surface is clean, and sensor is mounted correctly. Using feeler gauge, measure air gap between sensor and tone ring teeth. Repeat measurement in at least 2 more positions to ensure air gap does not vary as wheel is turned. Air gap should be less than .070" (1.8 mm) and measurement should be consistent. If air gap is not consistent, tone ring is not pressed on straight or axle end play is excessive. Check and repair as necessary. If air gap is more than specified, replace tone ring. If air gap is as specified, replace sensor. Go to next step.

  5. Recheck Sensor Output

    - Repeat step 3). If sensor output is more than 3.0 mV/Hz on AWD/4WD, or more than 5.0 mV/Hz for 2WD models, problem is corrected. Test drive vehicle. If sensor output is not okay, and tone ring is installed properly, replace sensor and check sensor output. Ensure air gap measurement is correct.

  6. Check For Wiring Intermittents

    - If all previous steps have been performed, and problem still exists, condition may be wiring related. Closely check Tan/Orange wire and Tan/Black wire between sensor and ABS control module. See SYMPTOM H: INTERMITTENT DIAGNOSIS PROCEDURE  under SYMPTOM TESTS. If condition still exists after intermittent diagnosis procedure is performed, go to next step. If problem is corrected, test drive vehicle.

  7. Check If Steps Have Been Completed

    - If this step is not completed, replacement of any system component without being instructed to do so may not correct system fault. This step requires that a valid code be present, completion of all prior steps, and affected wiring integrity verified. If all previous steps have not been completed as described above, return to last test step completed, and continue testing. If all prior steps have been completed as described above, replace wheel speed sensor and go to step 8). If condition still exists after completing step 8), replace ABS control module and repeat step 8).

  8. Speed Sensor Output Drive Test

    - Remove breakout box and adapter. Connect all components. Clear fault codes and cycle ignition key. Drive vehicle and complete at least one hard left and right turn. Travel over a rough road at steady speed. Perform one hard acceleration from a stop. At completion of test drive, check for fault codes. If SYSTEM PASS is set, repair is complete. If code other than Code C1158, C1233 or C1258 is set, go to appropriate trouble code test. If Code C1158, C1233 or C1258 still exists and ABS control module has been replaced, go to next step.

  9. Possible Conditions Not Checked

    - This step assumes that wiring integrity has been verified, and wheel speed sensor and ABS control module have been replaced. The following is time consuming and should be performed only after all previous possibilities have been exhausted. Inspect Tan/Orange wire and Tan/Black wire between wheel speed sensor and ABS control module. Check for chafing or any other damage that could cause an open or shorted condition. Repair wiring as necessary. If wiring is okay, inspect for excessive axle vibration, especially over rough road. Ensure front axle is operating correctly. Repair as necessary. If code still exists, repeat step 7).
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