Inspection Procedure 5

INSPECTION PROCEDURE 5: When the TCL Switch is Push On, TCL dose not be Cancelled.

TCL Switch System Circuit (Part 1):

TCL Switch System Circuit (Part 2):

CIRCUIT OPERATION
ABS/TCL-ECU terminal 6 is grounded every time the TCL switch is pressed. ABS/TCL-ECU monitors this operation state and turns the TCL ON or OFF.

COMMENT
The cause is probably an open-circuit in the TCL switch circuit.

TROUBLESHOOTING HINTS
- Malfunction of the TCL switch.
- Damaged harness or connector.
- Malfunction of the ABS/TCL-ECU.

DIAGNOSIS

Required Special Tools:
- MB991970: ABS Check Harness
- MB991223: Harness Set
- MB992006: Extra Fine Probe

STEP 1. Measure the terminal voltage at ABS/TCL-ECU connector A-02.




1. Disconnect the ABS/TCL-ECU connector A-02.




2. Connect special tool MB991970 between the ABS/TCL-EUC and the body-side harness connector.
3. Turn the ignition switch to the "ON" position.
4. Measure the terminal voltage between special tool MB991970 connector terminal 6 (ABS/TCL-ECU connector A-02 terminal 6) 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.

5. Turn the ignition switch to the "LOCK" (OFF) position.
6. Disconnect special tool MB991970 between the ABS/TCL-ECU and the body-side harness connector.
7. Connect the ABS/TCL-ECU connector A-02.

Q: Is the terminal voltage battery terminal 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.

1. Remove the TCL switch.




2. Connect an ohmmeter to the TCL switch between terminals 1 and 2.
3. 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. Then go to Step 3.

NO : Replace the TCL switch. Then go to Step 7.

STEP 3. Check ABS/TCL-ECU connector A-02, intermediate connector C-29 and TCL switch connectors C-131 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. Then go to Step 7.

STEP 4. Check the harness wire between ABS/TCL-ECU connector A-02 terminal 6 and TCL switch connector C-131 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-131 terminal 2 and ground for damage.
- Check the ground wire for open circuit.









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: Does TCL system cancelled, when the TCL switch is push on?

YES : It can be assumed that this malfunction is intermittent.

NO : Replace the hydraulic unit (integrated with ABS/TCL-ECU). Then go to Step 7.

STEP 7. Retest the system

Q: Does TCL system cancelled, when the TCL switch is push on?

YES : The procedure is complete.

NO : Return to Step 1.