Inspection Procedure 2

When the Brake Pedal is Depressed, Auto-cruise Control is not Cancelled.

Stoplight Switch Circuit Part 1:

Stoplight Switch Circuit Part 2:

CIRCUIT OPERATION
This is the stoplight switch input signal circuit. The signal is sent to the stoplight switch from dedicated fuse 5, and is then sent to the auto-cruise control-ECU.

TECHNICAL DESCRIPTION (COMMENT)
The cause is probably a malfunction of the stoplight switch circuit.

TROUBLESHOOTING HINTS
- Malfunction of the stoplight switch.
- Damaged harness or connector.
- Malfunction of the auto-cruise control-ECU.

DIAGNOSIS

Required Special Tool:
- MB991223: Harness Set

STEP 1. Check if the stoplight illuminates.

Q: Is the stoplight illuminated?

YES: Go to Step 8.

NO: Go to Step 2.

STEP 2. Check the 12-Volt supply circuit voltage at stoplight switch connector C-03 (terminal number 2).

1. Disconnect stoplight switch connector C-03 and measure at the harness side.




2. Measure the voltage between terminal 2 and ground.

Q: Is the voltage approximately battery positive voltage?

YES: Go to Step 5.

NO: Go to Step 3.




STEP 3. Check stoplight switch connector C-03.

Q: Is the connector damaged?

YES: Repair or replace connector. Refer to Harness Connector Inspection. Then check that the malfunction is eliminated.

NO: Go to Step 4.




STEP 4. Check the harness wire between dedicated fuse No.5 and stoplight switch connector C-03 (terminal number 2).

Q: Is any harness wire between dedicated fuse No.5 and stoplight switch connector C-03 (terminal number 2) damaged?

YES: Repair the harness wire and then check that the malfunction is eliminated.

NO: Check that the malfunction is eliminated. If the malfunction is not eliminated, replace the auto-cruise control-ECU. Then check that the malfunction is eliminated.

STEP 5. Check the stoplight switch.

1. Disconnect harness connector C-03 at the stoplight switch.







2. Connect an ohmmeter to the stoplight switch, and check continuity when the plunger of the stoplight switch is pushed in and when it is released.
3. The stoplight switch is in good condition if the circuit is open when the plunger is pushed in to a depth of within 4 mm (0.2 inch) from the outer case edge surface, and if the resistance value is less than 2 Ohm when it is released.
4. The check for continuity should be made at terminals 1 and 2 of the stoplight switch.

Q: Is the circuit open?

YES: Replace the stoplight switch. Refer to Brake Pedal. Then check that the malfunction is eliminated.

NO: Go to Step 6.







STEP 6. Check stoplight switch connector C-03 and intermediate connector C-89.

Q: Is any connector damaged?

YES: Repair or replace connector. Refer to Harness Connector Inspection. Then check that the malfunction is eliminated.

NO: Go to Step 7.







STEP 7. Check the harness wire between stoplight switch connector C-03 (terminal number 1) and intermediate connector C-89 (terminal number 14).

Q: Is any harness wire between stoplight switch connector C-03 (terminal number 1) and intermediate connector C-89 (terminal number 14) damaged?

YES: Repair the harness wire and then check that the malfunction is eliminated.

NO: Check that the malfunction is eliminated. If the malfunction is not eliminated, replace the auto-cruise control-ECU. Then check that the malfunction is eliminated.

STEP 8. Check the output circuit voltage at auto-cruise control-ECU connector C-20 (terminal number 4) by backprobing.

1. Do not disconnect auto-cruise control switch connector C-20.
2. Turn the ignition switch to the "ON" position.




3. Measure the voltage between terminal 4 and ground by backprobing.
- Voltage should be battery positive volts. (When brake pedal is depressed.)
- Voltage should be 0.5 volts or less. (When brake pedal is not depressed.)

4. Turn the ignition switch to the "LOCK" (OFF) position.

Q: Is the voltage within specifications?

YES: Check that the malfunction is eliminated. If the malfunction is not eliminated, replace the auto-cruise control-ECU. Then check that the malfunction is eliminated.

NO: Go to Step 9.







STEP 9. Check auto-cruise control-ECU connector C-20 and intermediate connector C-89.

Q: Is the connector damaged?

YES: Repair or replace connector. Refer to Harness Connector Inspection. Then check that the malfunction is eliminated.

NO: Go to Step 10.







STEP 10. Check the harness wire between intermediate connector C-89 (terminal number 14) and auto-cruise control-ECU connector C-20 (terminal number 4).

Q: Is any harness wire between intermediate connector C-89 (terminal number 14) and auto-cruise control-ECU connector C-20 (terminal number 4) damaged?

YES: Repair the harness wire and then check that the malfunction is eliminated.

NO: Check that the malfunction is eliminated. If the malfunction is not eliminated, replace the auto-cruise control-ECU. Then check that the malfunction is eliminated.