INSPECTION PROCEDURE C-5: Central Door Locking System: All the doors do not lock with just the driver's inside lock knob lock operation.: 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 a 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.- Connect scan tool MB991502 to the data link connector.
- 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: Scan tool MB991502 does not sound when the driver's inside lock knob is locked or unlocked: Refer to INSPECTION PROCEDURE O-10 "THE DRIVER'S OR PASSENGER'S DOOR LOCK ACTUATOR SWITCH SIGNAL IS NOT SENT TO THE ETACS-ECU ."
- STEP 3. Check the input signal (by using a voltmeter).
Check the input signal from the driver's door lock actuator switch.
- Use special tool MB991529 to connect a voltmeter between ground terminal 4 or 5 and ETACS-ECU terminal 9 of the data link connector.
- 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: The voltmeter needle does not fluctuate when the driver's inside lock knob is locked or unlocked: Refer to INSPECTION PROCEDURE O-10 "THE DRIVER'S OR PASSENGER'S DOOR LOCK ACTUATOR SWITCH SIGNAL IS NOT SENT TO THE ETACS-ECU ."