Inspection Procedure 10

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














CIRCUIT OPERATION

TCL/ASC-ECU terminal 15 is grounded every time the TCL switch is pressed. TCL/ASC-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, connector
- Malfunction of the TCL/ASC-ECU

DIAGNOSIS

Required Special Tools:

- MB991223: Harness Set
- MB991952: ABS Check Harness
- MB992006: Extra Fine Probe

STEP 1. Measure the terminal voltage at TCL/ASC-ECU connector A-32.





(1)Disconnect the TCL/ASC-ECU connector A-32.





(2)Connect special tool MB991952 between the TCL/ASC-ECU and the body-side harness connector A-32.
(3)Turn the ignition switch to the "ON" position.
(4)Measure the terminal voltage between special tool MB991952 connector terminal 15
(TCL/ASC-ECU connector A-32 terminal 15) 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 MB991952 between the TCL/ASC-ECU and the body-side harness connector A-32.
(7)Connect the TCL/ASC-ECU connector A-32.

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.

(1)Remove the TCL switch. (Refer to Service and Repair).





(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. (Refer to Service and Repair). Then go to Step 3.

NO Replace the TCL switch. (Refer to Service and Repair). Then go to Step 7.

STEP 3. Check TCL/ASC-ECU connector A-32, intermediate connector C-31 and TCL switch connectors C-35 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. Harness Connector Inspection). Then go to Step 7.

STEP 4. Check the harness wire between TCL/ASC-ECU connector A-32 terminal 15 and TCL switch connector C-35 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-35 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 push on?

YES It can be assumed that this malfunction is intermittent. How to Cope With Intermittent Malfunctions).
NO Replace the hydraulic unit (integrated with TCL/ASC-ECU). Service and Repair). Then go to Step 7.
STEP 7. Retest the system

Q. Is TCL cancelled when the TCL switch is push on?

YES The procedure is complete.
NO Return to Step 1.