DTC C0108 Front Abs Wheel Speed Sensor LH Malfunction (Abs Wheel Speed Sensor Abnormal Signal)
DTC DETECTING CONDITION:
- Defective ABS wheel speed sensor signal (noise, abnormal signal, etc.)
- Defective harness connector
TROUBLE SYMPTOM:
ABS does not operate.
WIRING DIAGRAM:
Fig 1: Front ABS Wheel Speed Sensor LH Malfunction (ABS Wheel Speed Sensor Abnormal Signal) - Wiring Diagram
DIAGNOSIS PROCEDURE
| Step | Check | Yes | No |
|---|---|---|---|
1 CHECK OUTPUT OF ABS WHEEL SPEED SENSOR USING SUBARU SELECT MONITOR.
|
Does the speed indicated on the display change in response to the speedometer reading during acceleration/deceleration when the steering wheel is in the straight-ahead position? | Go to step 2. | Go to step 7. |
| 2 CHECK POOR CONTACT IN CONNECTOR. Turn the ignition switch to OFF. |
Is there poor contact in connectors between ABSCM&H/U and ABS wheel speed sensor? | Repair the connector. | Go to step 3. |
| 3 CHECK CAUSE OF SIGNAL NOISE. Make sure the radio wave devices and electric components car phone, radio, etc. are installed correctly. |
Are the radio wave devices and electric components installed correctly? | Go to step 4. | Install the radio wave devices and electric components properly. |
| 4 CHECK CAUSE OF SIGNAL NOISE. Check if the noise sources (such as an antenna) are installed near the sensor harness. |
Are noise sources installed? | Install the noise sources apart from sensor harness. | Go to step 5. |
5 CHECK ABSCM&H/U.
|
Is the same DTC displayed? | Replace the ABSCM only. < Ref. to REPLACEMENT , ABS Control Module and Hydraulic Control Unit (ABSCM&H/U). > | Go to step 6. |
| 6 CHECK ANY OTHER DTC ON DISPLAY. | Is there any other DTC displayed? | Perform the diagnosis according to DTC. | It results from a temporary noise interference. |
| 7 CHECK INSTALLATION OF ABS WHEEL SPEED SENSOR. | Is the ABS wheel speed sensor installation bolt tightened 7.5 N.m (0.76 kgf-m, 5.5 ft-lb)? | Go to step 8. | Tighten the ABS wheel speed sensor installation bolts. |
8 CHECK ABS WHEEL SPEED SENSOR SIGNAL.
|
Does the oscilloscope indicate the waveform pattern like shown in the figure when the tire is slowly turned? Does the oscilloscope indication repeat the waveform pattern like shown in the figure when the tire is slowly turned in equal speed for more one rotation? | Go to step 10. | Go to step 9. |
| 9 CHECK ABS WHEEL SPEED SENSOR OR MAGNETIC ENCODER. | Are there foreign matter, breakage or damage at the tip of ABS wheel speed sensor or magnetic encoder? | Remove dirt thoroughly. Also replace the ABS wheel speed sensor or magnetic encoder as a unit with hub unit bearing if it is broken or damaged. | Go to step 10. |
| 10 CHECK CAUSE OF SIGNAL NOISE. Make sure the radio wave devices and electric components car phone, radio, etc. are installed correctly. |
Are the radio wave devices and electric components installed correctly? | Go to step 11. | Install the radio wave devices and electric components properly. |
| 11 CHECK CAUSE OF SIGNAL NOISE. Check if the noise sources (such as an antenna) are installed near the sensor harness. |
Is the noise sources installed? | Go to step 12. | Install the noise sources apart from sensor harness. |
12 CHECK ABSCM&H/U.
|
Is the same DTC displayed? | Replace the ABSCM only. < Ref. to REPLACEMENT , ABS Control Module and Hydraulic Control Unit (ABSCM&H/U). > | Go to step 13. |
| 13 CHECK ANY OTHER DTC ON DISPLAY. | Is there any other DTC displayed? | Perform the diagnosis according to DTC. | It results from a temporary noise interference.
NOTE:
Though the ABS warning light remains on at this time, this is normal. Drive the vehicle at more than 12km/h (7 MPH) in order to turn ABS warning light off. Be sure to drive the vehicle and check that the warning light goes off.
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