Inspection Procedure C-1

Central door locking system: Central door locking system does not operate.

Door Lock Actuator Circuit:

Connectors:

CIRCUIT OPERATION
- The ETACS-ECU operates the door lock actuators through its dedicated relay (integrated in the ETACS-ECU).
- The ETACS-ECU drives the relay to lock or unlock the door if the requirements are satisfied.

TECHNICAL DESCRIPTION (COMMENT)
The power supply circuit, the circuit shared by door lock actuators, or the ETACS-ECU may be defective.

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

DIAGNOSIS

Required Special Tool:
- MB991223: Harness Set

STEP 1. Check the ETACS-ECU power supply circuit (for door lock/unlock relay) at the ETACS- ECU connector C-311.
1. Disconnect the ETACS-ECU connector C-311 and measure at the junction block side.




2. Measure the voltage between terminal 16 and ground.

Q: Is the voltage approximately 12 volts (battery positive voltage)?

YES: Go to Step 4.
NO: Go to Step 2.




STEP 2. Check the junction block connector C-311 for damage.

Q: Is junction block connector C-311 in good condition?

YES: Go to Step 3.
NO: Repair or replace it. Refer to Harness Connector Inspection. The central door locking system should work normally.










STEP 3. Check the harness wires between ETACS-ECU connector C-311 and fusible link (2).

NOTE: After checking junction block connector C-309 and intermediate connector C-209, check the wires. If junction block connector C-309 and intermediate connector C-209 are damaged, repair or replace them. Refer to Harness Connector Inspection.

Q: Are the harness wires between ETACS-ECU connector C-311 and fusible link (2) in good condition?

YES: There is no action to be taken.
NO: Repair them. The central door locking system should work normally.




STEP 4. Check the junction block connector C-311 for damage.

Q: Is junction block connector C-311 in good condition?

YES: Go to Step 5.
NO: Repair or replace it. Refer to Harness Connector Inspection. The central door locking system should work normally.













STEP 5. Check the harness wires between ETACS-ECU connector C-311 and driver's door lock actuator connector E-13.

NOTE: After checking junction block connectors C-303 and C-308 and intermediate connector C-211, check the wires. If junction block connectors C-303 and C-308 and intermediate connector C-211 are damaged, repair or replace them. Refer to Harness Connector Inspection.

Q: Are the harness wires between ETACS-ECU connector C-311 and driver's door lock actuator connector E-13 in good condition?

YES: Replace the ETACS-ECU. The central door locking system should work normally.
NO: Repair them. The central door locking system should work normally.