Inspection Procedure C-5

Central door locking system: All the doors do not lock with just the driver's inside lock knob lock operation.

TECHNICAL DESCRIPTION (COMMENT)
The driver's door lock actuator switch or the ETACS-ECU may be defective.

TROUBLESHOOTING HINTS
- Malfunction of the driver's door lock actuator switch
- Damaged harness wires or connectors

DIAGNOSIS

Required Special Tools:
- MB991223: Test Harness Set
- MB991502: Scan Tool (MUT-II)
- MB991529: Diagnostic Trouble Code Check Harness

STEP 1. Check method of the input signal

Q: Which is to be used, the scan tool or the voltmeter to check the input signal?

Scan tool MB991502: Go to Step 2.
Voltmeter: Go to Step 3.

STEP 2. Check the input signal (by using scan tool MB991502).
Check the input signal from the driver'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.




1. Connect scan tool MB991502 to the data link connector.
2. Check that the tone alarm of scan tool MB991502 sounds when the input signal enters.

Q: Does the tone alarm of scan tool MB991502 sound when the input signal enters?

YES: Replace the ETACS-ECU. All doors should be locked by using the driver's inside lock knob.
NO: Check the driver's door lock actuator switch input circuit. Refer to Inspection Procedure O-10.

STEP 3. Check the input signal (by using a voltmeter).
Check the input signal from the driver's door lock actuator switch.




1. Use special tool MB991529 to connect a voltmeter between ground terminal 4 or 5 and ETACS-ECU terminal 9 of the data link connector.
2. Check that the voltmeter indicator deflects once when the input signal enters.

Q: Does the voltmeter indicator deflect?

YES: Replace the ETACS-ECU. All doors should be locked by using the driver's inside lock knob.
NO: Check the driver's door lock actuator switch input circuit. Refer to Inspection Procedure O-10.