Inspection Procedure
7: ASC OFF indicator lamp stays ON after the engine is started.
caution |
- If
there is any problem in the CAN bus lines, an incorrect diagnosis code may be set. Prior to this
diagnosis, diagnose the CAN bus lines (Refer to GROUP 54C -
CAN Bus Diagnostics Table
).
- Whenever ECU is replaced, ensure that the CAN bus lines are normal.
- When the hydraulic unit (integrated with ASC-ECU) is replaced, always carry out
the calibration of the G and yaw rate sensor and the steering wheel sensor (Refer to
and ).
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OPERATION
- ASC-ECU sends the illumination request signal of the ASC OFF indicator lamp
to the combination meter via the CAN communication.
- ASC-ECU illuminates ASC OFF indicator lamp for approximately 3 seconds for bulb
check with the ignition switch turned to the ON position.
- When the ASC OFF switch is pressed for three seconds or more, the ASC system will
be deactivated.
- When the ASC OFF switch is pressed for 15 seconds or more, the ASC system will be
held in ON state and it cannot be deactivated until the ignition switch is turned to the ON
position the next time.
COMMENTS ON TROUBLE SYMPTOM
This may be caused by faults in the CAN bus line, combination meter or ASC-ECU.
PROBABLE CAUSES
- The CAN bus line is defective.
- Damaged wiring harness and connectors
- Malfunction of the combination meter
- Malfunction of the ASC OFF switch
- Malfunction of the hydraulic unit assembly (integrated with ASC-ECU)
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STEP 1. M.U.T.-III CAN bus diagnosis.
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Use the M.U.T.-III to diagnose the CAN bus lines.
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Q.
Is the check result normal?
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Go to Step 2.
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Repair the CAN bus line. (Refer to GROUP 54C -
Troubleshooting ).
Then go to Step 8.
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STEP 2. M.U.T.-III diagnosis code.
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Use M.U.T.-III to check the diagnosis code for the ASC system.
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Q.
Is the diagnosis code stored?
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Carry out the diagnosis for the diagnosis code (Refer to ).
Then go to Step 8.
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Go to Step 3.
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STEP 3. Measure the resistance at the ASC-ECU connector.
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(1)Check the ASC-ECU connector.
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(2)Disconnect the connector and measure at the wiring harness side.
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(3)Measure the resistance between SWON terminal and body earth. OK:
- When the ASC OFF switch is pressed: Continuity exists (2 Ω
or less)
- When the ASC OFF switch is not pressed: No continuity
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Q.
Is the check result normal?
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Go to Step 6.
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Go to Step 4.
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STEP 4. Check the ASC OFF switch.
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Refer to .
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Q.
Is the check result normal?
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Go to Step 5.
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Replace the ASC OFF switch (Refer to GROUP 52A -
Instrument Lower Panel ).
Then go to Step 8.
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STEP 5. Measure the resistance at the ASC OFF switch connector.
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(1)Check the ASC-ECU connector.
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(2)Check the ASC OFF switch connector.
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(3)Disconnect the connector and measure at the wiring harness side.
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(4)Measure the resistance between ASC-ECU connector SWON terminal and ASC OFF switch
and resistance between ASC OFF switch and body earth. OK: Continuity exists (2 Ω
or less)
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Q.
Is the check result normal?
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Go to Step 6.
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The circuit may be open. Repair the wiring harness wires or connectors between
ASC-ECU connector SWON terminal and ASC OFF switch and resistance between ASC OFF switch and
body earth. Then go to Step 8.
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STEP 6. M.U.T.-III Diagnosis code of other systems.
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Use M.U.T.-III to check if the diagnosis code is set in the combination meter system.
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Q.
Is the diagnosis code set?
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Perform troubleshooting for the combination meter. (Refer to GROUP 54A -
Combination
Meter, Troubleshooting ). Then go to Step 8.
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Go to Step 7.
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STEP 7. Retest the system.
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Q.
Does the ASC OFF indicator lamp turn ON and OFF normally?
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The trouble can be an intermittent malfunction (Refer to GROUP 00 -
How
to Cope with Intermittent Malfunction).
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Replace the hydraulic unit assembly (integrated with ASC-ECU) (Refer to ).
Then go to Step 8.
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STEP 8. Retest the system.
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Q.
Does the ASC OFF indicator lamp turn ON and OFF normally?
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This diagnosis is complete.
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Return to Step 1.
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