INSPECTION PROCEDURE 7: When the TCL Switch is Pushed On, TCL System is not Cancelled.: Diagnosis
Required Special Tools:
- MB991223: Harness Set
- MB991997: ASC Check Harness
- STEP 1. Measure the terminal voltage at ABS/TCL-ECU connector A-03.
- Connect special tool MB991997 between the ABS/TCL-ECU and the body-side harness connector A-03.
- Turn the ignition switch to the "ON" position.
- Measure the terminal voltage between special tool MB991997 connector terminal 38 (ABS/TCL-ECU connector A-03 terminal 38) and ground.
- When the TCL switch is not pressed, the voltage should measure battery positive voltage (approximately 12 volts).
- When the TCL switch is pressed, the voltage should measure 1 volt or less.
- Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the terminal voltage battery positive voltage when the TCL switch is not pressed, and is the terminal voltage 1 volt or less when the TCL switch is pressed?
YES : Go to Step 6.
NO : Go to Step 2.
- STEP 2. Check the TCL switch.
- Remove the TCL switch. (Refer to TCL SWITCH WHEEL SPEED SENSOR ).
- Connect an ohmmeter to the TCL switch between terminals 1 and 2.
- Check for continuity between terminals 1 and 2 when the TCL switch is operated.
- There is no continuity between terminals 1 and 2 when the TCL switch is not pressed.
- There is continuity between terminals 1 and 2 when the TCL switch is pressed.
Q: Is there no continuity between terminals 1 and 2 when the TCL switch is not pressed, and is there continuity when the TCL switch is pressed?
YES : Install the TCL switch. (Refer to TCL SWITCH ). Then go to Step 6.
NO : Replace the TCL switch. (Refer to TCL SWITCH ). Then go to Step 7.
- STEP 3. Check ABS/TCL-ECU connector A-03, intermediate connector C-24 and TCL switch connector C-126 for loose, corroded or damaged terminals, or terminals pushed back in the connector.
Q: Are there connectors and terminals in good condition?
YES : Go to Step 4.
NO : Repair or replace the faulty connector. (Refer to, HARNESS CONNECTOR INSPECTION ). Then go to Step 7.
- STEP 4. Check the harness wire between ABS/TCL-ECU connector A-03 terminal 38 and TCL switch connector C-126 terminal 1 for damage.
Q: Are there harness wires in good condition?
YES : Go to Step 5.
NO : Repair the damaged harness wire. Then go to Step 7.
- STEP 5. Check the harness wire between TCL switch connector C-126 terminal 2 and ground for damage.
Q: Is the harness wire in good condition?
YES : Go to Step 6.
NO : Repair the damaged harness wire. Then go to Step 7.
- STEP 6. Retest the system
Q: Is TCL cancelled when the TCL switch is pushed on?
YES : It can be assumed that this malfunction is intermittent. (Refer to, How to Use Troubleshooting/Inspection Service Points - HOW TO COPE WITH INTERMITTENT MALFUNCTION ).
NO : Replace the hydraulic unit (integrated with ABS/TCL-ECU). Then go to Step 7.
- STEP 7. Retest the system
Q: Is TCL cancelled when the TCL switch is pushed on?
YES : The procedure is complete.
NO : Return to Step 1.