Inspection Procedure J-6

TECHNICAL DESCRIPTION (COMMENT)
The ETACS-ECU operates the headlight automatic shutdown function, based on the signals from the following switches:
- Ignition switch (IG1)
- Driver's door switch
- Taillight switch
- Headlight switch

If the function does work normally, a defect on relevant input circuits, the ETACS-ECU or the front-ECU is suspected.

TROUBLESHOOTING HINTS
- Malfunction of the driver's door switch
- Malfunction of the taillight switch
- Malfunction of the headlight switch
- Malfunction of the ETACS-ECU
- Malfunction of the front-ECU
- 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 the DTC.
If the DTC sets when the ignition switch is turned to "LOCK" (OFF) position, carry out the troubleshooting by referring to Diagnostic Trouble Code Chart. If the DTC does not set, go to Step 2.

STEP 2. Check the input signal.
Check the input signals from the following switches.
- Ignition switch (IG1)
- Driver's door switch
- Taillight switch
- Headlight switch






CAUTION: To prevent damage to scan tool MB991502, always turn the ignition switch to "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.





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.
If one of the input signal checks shows a defect, check the relevant input circuit.
If no defect appears, replace the ETACS-ECU or front-ECU.
The headlight automatic shutdown function should work normally.