Inspection Procedure I-9

Headlight, Tail Light: Headlight Automatic Shutdown Function does not Work Normally

Headlight Automatic Shut-down Function:

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 headlight automatic shutdown function according to the following signals:
- Ignition switch (IG1)
- Driver's door switch
- Tail light switch
- Headlight switch

TECHNICAL DESCRIPTION (COMMENT)
If the function does not work normally, the input circuit system from the switches, the ETACS-ECU or the front-ECU may be defective (refer to "CIRCUIT OPERATION").

TROUBLESHOOTING HINTS
- Malfunction of the driver's door switch
- Malfunction of the column switch (turn-signal light and lighting 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)
- MB991862: SWS monitor kit

STEP 1. Check the configuration function.

Q: Has the headlight automatic shutdown function been enabled by means of the adjustment function?

YES: Go to Step 2.

NO: Enable the headlight automatic shutdown function been by means of the adjustment function.

STEP 2. Check the input signal by using service data of the SWS monitor.

Check the input signals from the following switches:
- ignition switch: "ON" to "OFF"
- lighting switch: "TAIL" or "HEAD"

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. Select "LIGHTING - H/L AUTO-CUT" (FUNCTION DIAG), and check that normal conditions are displayed on the items described in the table.




4. When the driver's door is opened, check that normal conditions are displayed on the items described in the table.

Q: Are normal conditions displayed on the "TAILLIGHT SW", "IG SW (IG1)", "FRONT DOOR SW" and "H/L AUTO-CUT"?

YES: Replace the front-ECU. Check that the headlight automatic shutdown function works normally.

NO:
- Normal condition is not displayed on the "TAIL LIGHT SW: Refer to Inspection Procedure L-5 "ETACS-ECU does not receive a signal from the tail light switch."
- Normal condition is not displayed on the "IG SW (IG1)": Refer to Inspection Procedure L-2 "ETACS-ECU does not receive a signal from the ignition switch (IG1)."
- Normal condition is not displayed on the "FRONT DOOR SW": Refer to Inspection Procedure L-5 "ETACS-ECU does not receive a signal from the driver's or the front passenger's door switch."
- Normal condition is not displayed on the "H/L AUTO-CUT": Replace the front-ECU. Check that the headlight automatic shutdown function works normally.