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Home >> Jeep >> 2004 >> Liberty Limited, 4WD, Automatic >> Repair and Diagnosis >> Brakes >> Traction Control >> Anti-Lock Brake System >> Electronic Testing >> Left Front, Right Front Or Rear Sensor Circuit Failure >> Testing

Left Front, Right Front Or Rear Sensor Circuit Failure: Testing

    NOTE: The CAB must sense all four wheels at 25 km/h (15 mph) before it will extinguish the ABS indicators.
  1. Turn the ignition on. With the DRBIII®, read DTC's. With the DRBIII®, read Freeze Frame information. With the DRBIII®, erase DTC's. Turn the ignition off. Turn the ignition on. With the DRBIII®, read DTC's. Does the DRBIII® display SENSOR CIRCUIT FAILURE? Yes, go to next step. No, go to step  13.
  2. Turn the ignition off. Inspect the CAB connector, affected Wheel Speed Sensor, and affected Wheel Speed Sensor connector. Is the affected Wheel Speed Sensor or any of the connectors damaged? Yes, repair as necessary. Perform ABS VERIFICATION TEST VER-1 . No, go to next step.
  3. Turn the ignition off. Disconnect the affected wheel speed sensor connector. Check connector and clean or repair as necessary. Turn the ignition on. Measure the voltage between affected Wheel Speed Sensor 12 volt supply circuit and ground. Is the voltage above 10 volts? Yes, go to step  5. No, go to next step.
  4. Turn the ignition off. Disconnect the CAB harness connector. Disconnect the affected Wheel Speed sensor connector. Using a 12-volt test light connected to 12-volts, probe the affected Wheel Speed sensor 12 volt supply circuit. Does the test light illuminate? Yes, repair the affected Wheel Speed Sensor 12 volt supply circuit for a short to ground. See ABS VERIFICATION TEST VER-1 . No, go to next step.
  5. Turn the ignition off. Disconnect the CAB harness connector. Disconnect the affected Wheel Speed Sensor connector. Connect a jumper wire between affected Wheel Speed Sensor 12 volt supply circuit and ground. Using a 12-volt test light connected to 12-volts, probe the affected Wheel Speed Sensor 12 volt supply circuit. Does the test light illuminate? Yes, go to next step. No, repair the affected Wheel Speed Sensor 12 volt supply circuit for an open. See ABS VERIFICATION TEST VER-1 .
  6. Turn the ignition off. Disconnect the CAB harness connector. Disconnect the affected Wheel Speed Sensor connector. Check connector, clean or repair as necessary. Turn the ignition on. Measure the voltage between affected Wheel Speed Sensor circuit and ground. Is the voltage above 1 volt? Yes, repair the affected wheel speed sensor signal circuit for a short to voltage. See ABS VERIFICATION TEST VER-1 . No, go to next step.
  7. Turn the ignition off. Disconnect the CAB harness connector. Disconnect the affected Wheel Speed Sensor connector. Using a 12-volt test light connected to 12-volts, probe the affected Wheel Speed Sensor Signal circuit. Does the test light illuminate? Yes, repair the affected Wheel Speed Sensor Signal circuit for a short to ground. See ABS VERIFICATION TEST VER-1 . No, go to next step.
  8. Turn the ignition off. Disconnect the CAB harness connector. Disconnect the affected Wheel Speed Sensor connector. Connect a jumper wire between affected Wheel Speed Sensor Signal circuit and ground. Using a 12-volt test light connected to 12-volts, probe the affected Wheel Speed Sensor Signal circuit. Does the test light illuminate? Yes, go to next step. No, repair the affected Wheel Speed Sensor Signal circuit for an open. See ABS VERIFICATION TEST VER-1 .
  9. Turn the ignition off. Remove the CAB harness strain relief to access wires. Reconnect the CAB harness connector. Turn the ignition on. Measure the voltage between affected Wheel Speed Sensor 12 volt supply circuit and ground. Is the voltage above 10 volts? Yes, go to next step. No, replace the Controller Antilock Brake in accordance with the service information. See ABS VERIFICATION TEST VER-1 .
  10. Turn the ignition off. Remove the CAB harness strain relief to access wires. Reconnect the CAB harness connector. Turn the ignition on. Measure the voltage between affected Wheel Speed Sensor 12 volt supply circuit and affected Wheel Speed Sensor Signal circuit. Is the voltage above 10 volts? Yes, go to next step. No, replace the Controller Antilock Brake in accordance with the service information. See ABS VERIFICATION TEST VER-1 .
  11. Turn the ignition off. Reconnect ALL affected Wheel Speed Sensor circuit connectors. Disconnect the affected Wheel Speed Sensor connector. Turn the ignition on. Measure the voltage of the affected Wheel Speed Sensor 12 volt supply circuit in the affected Wheel Speed Sensor connector while reconnecting the sensor connector. Did the affected Wheel Speed Sensor 12 volt supply circuit drop voltage to 0 DC volts? Yes, replace the affected Wheel Speed Sensor in accordance with the service information. See ABS VERIFICATION TEST VER-1 . No, go to next step.
  12. Turn the ignition off. Reconnect ALL affected Wheel Speed Sensor circuit connectors. Turn the ignition on. Measure the DC voltage of the Wheel Speed Sensor circuit in the affected Wheel Speed Sensor connector. Slowly rotate the wheel. Does the DC voltage toggle between 1.6 volts to 0.8 volts? Yes, go to next step. No, replace the affected Wheel Speed Sensor in accordance with the service information. See ABS VERIFICATION TEST VER-1 .
  13. Turn the ignition off. Visually inspect the related wiring harness. Look for any chafed, pierced, pinched, or partially broken wires. Visually inspect the related wire harness connectors. Look for broken, bent, pushed out, or corroded terminals. Refer to any hotline information or Technical Service Bulletins that may apply. Were any problems found? Yes, repair as necessary. Perform ABS VERIFICATION TEST VER-1 . No, test is complete.
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