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Home >> Mitsubishi >> 2009 >> Eclipse L4-2.4L (4G69) >> Repair and Diagnosis >> A L L Diagnostic Trouble Codes ( DTC ) >> Testing and Inspection >> C Code Charts >> C1206 >> ABS

ABS

DTC C1206: Front Left Wheel Speed Sensor (Abnormal Output Signal)





CAUTION
If there is any problem in the CAN bus lines, an incorrect diagnostic trouble code may be set. Prior to this diagnosis, diagnose the CAN bus lines.

CIRCUIT OPERATION
^ A toothed wheel speed rotor generates a voltage pulse as it moves across the pickup field of each wheel speed sensor.
^ The amount of voltage generated at each wheel is determined by the clearance between the wheel speed rotor teeth and the wheel speed sensor, and by the speed of rotation.
^ Sensor signal, which will not be created under normal operation
^ Sends alternating current signals at frequencies which are proportional to the rotation speeds of each wheel to the ABS electronic control unit (ABS-ECU).
^ The ABS hydraulic unit modulates the amount of braking force individually applied to each wheel cylinder.

ABS DTC SET CONDITIONS
The ABS-ECU monitors the signals from each wheel speed sensor while the vehicle is being driven. If any fault below is found in these sensor signals, the ECU will set the relevant diagnostic trouble code.
^ Missing sensor signal
^ Significant difference among the wheel speed sensor signals

TROUBLESHOOTING HINTS (THE MOST LIKELY CAUSES FOR THESE DTCS ARE TO SET ARE:)

Current trouble
^ Malfunction of the wheel speed sensor or wheel speed rotor
^ Damaged wiring harness or connector
^ Malfunction of the hydraulic unit (integrated with ABS-ECU)

Past trouble
^ Carry out diagnosis with particular emphasis on connector(s) or wiring harness in wheel speed sensor circuit. For diagnosis procedures, refer to "How to treat past trouble".

DIAGNOSIS

Required Special Tools:
^ MB991958: Scan Tool (M.U.T.-III Sub Assembly)
^ MB991824: V.C.I.
^ MB991827: M.U.T.-III USB Cable
^ MB991910: M.U.T.-III Main Harness A
^ MB991974: ABS Check Harness

STEP 1. Using scan tool MB991958, diagnose the CAN bus line.

CAUTION





To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.

1) Connect scan tool MB991958 to the data link connector.
2) Turn the ignition switch to the "ON" position.
3) Diagnose the CAN bus line.
4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the CAN bus line found to be normal?
YES: Go to Step 3
NO: Repair the CAN bus line. Then go to Step 2.

STEP 2. Recheck for diagnostic trouble code.

CAUTION





To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.

1) Turn the ignition switch to the "ON" position.
2) Erase the DTC.
3) Turn the ignition switch to the "LOCK" (OFF) position.
4) Turn the ignition switch to the "ON" position.
5) Check if the DTC is set.
6) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is DTC C1206 set?
YES: Go to Step 3
NO: The procedure is complete.

STEP 3. Using scan tool MB991958, read the diagnostic trouble code.

CAUTION





To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.

Use scan tool MB991958 to check whether DTC C1205 have been set simultaneously.
1) Connect scan tool MB991958 to the data link connector.
2) Turn the ignition switch to the "ON" position.
3) Check whether DTC C1205 have been set.
4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is DTC C1205 set?
YES: Carry out diagnosis relevant to DTC C1205.
NO: Go to Step 4.

STEP 4. Check the installation condition of the wheel speed sensors.
For the wheel speed sensor, which the DTC indicates, check whether the sensor or its mounting bolts are loosened.
^ DTC C1206 is set: Front left wheel speed sensor
Q: Is the wheel speed sensor installed correctly?
YES: Go to Step 5.
NO: Reinstall the wheel speed sensor correctly. Then go to Step 13.

STEP 5. Check the wheel speed sensor after it is removed from the vehicle.
Check the wheel speed sensor which the DTC indicates.
^ DTC C1206 is set: Front left wheel speed sensor
Q: Is the wheel speed sensor in good condition?
YES: Go to Step 6.
NO: Replace the wheel speed sensor. Then go to Step 13.

STEP 6. Check the wheel bearing for looseness.

NOTE: If the wheel bearing is loose, the gap between the wheel speed sensor and rotor may become excessive. Check the wheel bearing, which DTC indicates, for looseness.

^ DTC C1206 is set: Check the front right wheel bearing.
Q: Is the wheel bearing end play within the standard value?
YES: Go to Step 7.
NO: Replace the front hub assembly.

STEP 7. Check the wheel speed rotor.
Check the wheel speed rotor, which DTC indicates, for foreign material or deformation.
^ DTC C1206 is set: Front left wheel speed sensor
Q: Is the wheel speed rotor in good condition?
YES: Go to Step 8.
NO: If the wheel speed rotor is contaminated with foreign material, clean it. If the driveshaft is deformed, replace it.

STEP 8. Measure the voltage at ABS-ECU connector A-02.





1) Disconnect the connector A-02, and connect special tool MB991974 to the wiring harness-side connector.

NOTE: Do not connect special tool MB991974 to the ABS-ECU.

2) Turn the ignition switch to the "ON" position.
3) Measure the voltage between terminal 18 and body ground, and between terminal 19 and body ground. It should be 1V or less.
Q: Does the voltage measure 1V or less?
YES: Go to Step 9.
NO: Go to Step 11.

STEP 9. Measure the resistance at ABS-ECU connector A-02.





1) Disconnect the connector A-02, and connect special tool MB991974 to the wiring harness-side connector.

NOTE: Do not connect special tool MB991974 to the ABS-ECU.

2) Measure the resistance between terminal 18 and body ground, and between terminal 19 and body ground. There should be no continuity.
Q: Does continuity exist?
YES: Go to Step 11.
NO: Go to Step 10.

STEP 10. Measure the resistance at ABS-ECU connector A-02.





1) Disconnect the connector A-02, and connect special tool MB991974 to the wiring harness-side connector.

NOTE: Do not connect special tool MB991974 to the ABS-ECU.

2) Measure the resistance between terminal 18 and terminal 19.
Standard Value: 1.24 - 1.64 k ohms
Q: Is the resistance between terminals 18 and 19 within the standard value?
YES: Go to Step 12.
NO: Go to Step 11.

STEP 11. Inspect the wheel speed sensor.
Check the front left wheel speed sensor relevant to the DTC. For the applicable inspection procedure.
Q: Is the wheel speed sensor damaged?
YES: Replace the wheel speed sensor.
NO: Go to Step 12.

STEP 12. Check ABS-ECU connector A-02 and wheel speed sensor [front: LH] connector A-06 for loose, corroded or damaged terminals, or terminals pushed back in the connector.








Q: Are ABS-ECU connector A-02 and wheel speed sensor [front: LH] connector A-06 damaged?
YES: Repair or replace the damaged component(s). Then go to Step 14.
NO: Open or short circuit may be present in the front right wheel speed sensor circuit. Repair the wiring harness between ABS-ECU connector A-02 (terminals 18 and 19) and front left wheel speed sensor A-06 (terminals 1 and 2). Then go to Step 14.

STEP 13. Recheck for diagnostic trouble code.

CAUTION





To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.

Check again if the DTC is set.
1) Turn the ignition switch to the "ON" position.
2) Erase the DTC
3) Turn the ignition switch to the "LOCK" (OFF) position.
4) Turn the ignition switch to the "ON" position.
5) Check if the DTC is set.
6) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is DTC C1206 set?
YES: Replace the hydraulic unit (integrated with ABS-ECU). Then go to Step 14.
NO: It can be assumed that this malfunction is intermittent.

STEP 14. Recheck for diagnostic trouble code.

CAUTION





To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.

Check again if the DTC is set.
1) Turn the ignition switch to the "ON" position.
2) Erase the DTC
3) Turn the ignition switch to the "LOCK" (OFF) position.
4) Turn the ignition switch to the "ON" position.
5) Check if the DTC is set.
6) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is DTC C1206 set?
YES: Go to Step 1.
NO: The procedure is complete.

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