Inspection Procedure C-1

Central Door Locking System: The Central Door Lock System does not Work at All

Central Door Lock Power Supply Circuit:

Connectors:

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".

CIRCUIT OPERATION
- The ETACS-ECU operates the central door lock system according to the following signals:
- Driver's or passenger's door lock actuator switch
- Driver's side door lock key cylinder switch
- Door lock switch, which is incorporated in the power window main switch or power window sub switch (front RH)
- The ETACS-ECU locks or unlocks all the doors by operating the central door lock relay (incorporated in the ECU) in response to input signals.

TROUBLESHOOTING HINTS
- Malfunction of the ETACS-ECU
- Damaged harness wires or connectors

DIAGNOSIS

Required Special Tools:
- MB991223: Test Harness Set
- MB991502: Scan Tool (MUT-II)
- MB991862: SWS monitor kit







STEP 1. Use scan tool to select "ECU CHECK" on the SWS monitor display.

Check the ETACS-ECU.

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. When the ignition switch is turned to the "LOCK" (OFF) position, scan tool MB991502 should show "OK" on the "ETACS ECU" menu.

Q: Is "OK" displayed on the "ETACS ECU" menu?

YES: Go to STEP 2.

NO: Refer to Inspection Procedure A-3 "Communication with ETACS-ECU is impossible."




STEP 2. Measure at ETACS-ECU connector C-226 in order to check the fusible link 1. line of power supply system to ETACS-ECU.

1. Disconnect ETACS-ECU connector C-226, and measure at the junction block side.
2. Measure the voltage between terminal 2 and ground.
- The measured value should be approximately 12 volts (battery positive voltage).

Q: Does the measured voltage correspond with this range?

YES: Go to Step 5.

NO: Go to Step 3.




STEP 3. Check ETACS-ECU connector C-226 for damage.

Q: Is ETACS-ECU connector C-226 in good condition?

YES: Go to Step 4.

NO: Repair or replace the connector. Refer to Harness Connector Inspection. Check that the central door locking system works normally.













STEP 4. Check the wiring harness between ETACS-ECU connector C-226 and fusible link 1.

NOTE: Also check junction block connector C-212 and intermediate connector C-126. If junction block connector C-212 or intermediate connectors C-126 is damaged, repair or replace the connector as described in Harness Connector Inspection.

Q: Is the wiring harness between ETACS-ECU connector C-226 and fusible link 1. in good condition?

YES: No action to be taken.

NO: Repair the wiring harness. Check that the central door locking system works normally.








STEP 5. Check ETACS-ECU connectors C-226, C-227 and driver's door lock actuator connector E-04 for damage.

Q:Are ETACS-ECU connectors C-226, C-227 and driver's door lock actuator connector E-04 in good condition?

YES: Go to Step 6.

NO: Repair or replace the connector. Refer to Harness Connector Inspection. Check that the central door locking system works normally.













STEP 6. Check the wiring harness from ETACS-ECU connectors C-226 and C-227 to driver's door lock actuator connector E-04.

NOTE: Also check junction block connector C-214 and intermediate connector C-17. If junction block connector C-214 or intermediate connectors C-17 is damaged, repair or replace the connector as described in Harness Connector Inspection.

Q: Is the wiring harness from ETACS-ECU connectors C-226 and C-227 to driver's door lock actuator connector E-04 in good condition?

YES: Replace the ETACS-ECU. Check that the central door locking system works normally.

NO: Repair the wiring harness. Check that the central door locking system works normally.