Inspection Procedure O-6

The ETACS-ECU does not Receive Any Signal from the Driver's or the Front Passenger's Door Switch.

NOTE: This troubleshooting requires use of scan tool MB991502 and SWS monitor kit MB991862. For details of how to use the SWS monitor, refer to "How to use SWS monitor."

Front Door Switches Input Circuit:

Connectors:

CIRCUIT OPERATION
The ETACS-ECU operates the following functions or systems according to signal from the driver's or front passenger's door switches:
- Ignition key reminder tone alarm function
- Light reminder tone alarm function
- Power window timer function
- Headlight automatic shutdown function
- Dome light
- Interior automatic-shutdown function

TECHNICAL DESCRIPTION (COMMENT)
If the signal is not normal, the functions or systems, which are described in "CIRCUIT OPERATION", do not work normally. If the signal is not normal, the driver's or front passenger's door switch or the ETACS-ECU may be defective.

TROUBLESHOOTING HINTS
- Malfunction of the driver's or front passenger's door switches
- Malfunction of the ETACS-ECU
- Damaged harness wires or connectors

DIAGNOSIS

Required Special Tools:
- MB991223: Test Harness Set
- MB991502: Scan Tool (MUT-II)







STEP 1. Check the input signal by using service data of the SWS monitor.
Check the input signals from the driver's and front passenger's door lock actuator switch.

CAUTION: To prevent damage to scan tool MB991502, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991502. Also connect SWS monitor kit MB991862 after turning on scan tool MB991502.

1. Connect scan tool MB991502 to the data link connector.
2. Connect SWS monitor kit MB991862 to the column switch connector.




3. Select "ETACS-ECU" (DATA LIST), and check that normal conditions are displayed on the items described in the table.

Q: The scan tool shows the respective normal condition for item "DR DOOR SW" and "PASS DOOR SW."

YES: Replace the ETACS-ECU. If the functions, which are described in "CIRCUIT OPERATION", work normally, the input signal from the driver's or the front passenger's door switch should be normal.

NO:
- The scan tool does not show the respective normal condition for item "DR DOOR SW." Go to Step 2.
- The scan tool does not show the respective normal condition for item "PASS DOOR SW." Go to Step 6.







STEP 2. Check the driver's door switch.
Remove the Driver's door switch. Then check the continuity between the switch terminals and the switch body.

Q: Is the driver's door switch in good condition?

YES: Go to Step 3.

NO: Replace the driver's door switch. If the functions, which are described in "CIRCUIT OPERATION", work normally, the input signal from the driver's door switch should be normal.




STEP 3. Measure at the lower metal part of the driver's door switch in order to check the ground circuit to the driver's door switch.

NOTE: Check that the driver's door switch is grounded to the vehicle body by means of its mounting screw. Remove the cap, and measure the resistance value between the lower metal part and the ground.
- The measured value should be 2 ohm or less.

Q: Does the measured resistance value correspond with this range?

YES: Go to Step 4.

NO: Check the fit of the switch, and repair if necessary. If the functions, which are described in "CIRCUIT OPERATION", work normally, the input signal from the driver's door switch should be normal.










STEP 4. Check driver's door switch connector D-11 and ETACS-ECU connector C-119 for damage.

Q: Are driver's door switch connector D-11 and ETACS-ECU connector C-119 in good condition?

YES: Go to Step 5.

NO: Repair or replace the connector. Refer to Harness Connector Inspection. If the functions, which are described in "CIRCUIT OPERATION", work normally, the input signal from the driver's door switch should be normal.













STEP 5. Check the wiring harness between driver's door switch connector D-11 and ETACS-ECU connector C-119.

NOTE: Also check junction block connector C-101. If junction block connector C-101 is damaged, repair or replace the connector as described in Harness Connector Inspection.

Q: Is the wiring harness between driver's door switch connector D-11 and ETACS-ECU connector C-119 in good condition?

YES: Replace the ETACS-ECU. If the functions, which are described in "CIRCUIT OPERATION", work normally, the input signal from the driver's door switch should be normal.

NO: Repair the wiring harness. If the functions, which are described in "CIRCUIT OPERATION", work normally, the input signal from the driver's door switch should be normal.







STEP 6. Check the passenger's door switch.
Remove the passenger's door switch. Then check the continuity between the switch terminals and the switch body.

Q: Is the passenger's door switch in good condition?

YES: Go to Step 7.

NO: Replace the passenger's door switch. If the functions, which are described in "CIRCUIT OPERATION", work normally, the input signal from the passenger's door switch should be normal.




STEP 7. Measure at the lower metal part of the passenger's door switch in order to check the ground circuit to the passenger's door switch.

NOTE: Check that the passenger's door switch is grounded to the vehicle body by means of its mounting screw. Remove the cap, and measure the resistance value between the lower metal part and the ground.

- The measured value should be 2 ohm or less.

Q: Does the measured resistance value correspond with this range?

YES: Go to Step 8.

NO: Check the fit of the switch, and repair if necessary. If the functions, which are described in "CIRCUIT OPERATION", work normally, the input signal from the passenger's door switch should be normal.










STEP 8. Check passenger's door switch connector D-01 and ETACS-ECU connector C-118 for damage.

Q: Are passenger's door switch connector D-01 and ETACS-ECU connector C-118 in good condition?

YES: Go to Step 9.

NO: Repair or replace the connector. Refer to Harness Connector Inspection. If the functions, which are described in "CIRCUIT OPERATION", work normally, the input signal from the passenger's door switch should be normal.













STEP 9. Check the wiring harness between passenger's door switch connector D-01 and ETACS-ECU connector C-118.

NOTE: Also check intermediate connector C-90. If intermediate connectors C-90 is damaged, repair or replace the connector as described in Harness Connector Inspection.

Q: Is the wiring harness between passenger's door switch connector D-01 and ETACS-ECU connector C-118 in good condition?

YES: Replace the ETACS-ECU. If the functions, which are described in "CIRCUIT OPERATION", work normally, the input signal from the passenger's door switch should be normal.

NO: Repair the wiring harness. If the functions, which are described in "CIRCUIT OPERATION", work normally, the input signal from the passenger's door switch should be normal.