Inspection Procedure K-3

Interior Lamp: Front Dome Light and Rear Dome Light Dimming Function does not Work Normally

Interior Light Automatic Shut-down Function Circuit:

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 dome light dimming function according to the following switches:
- Ignition switch (IG1)
- Key reminder switch
- Front door switches
- Driver's door lock actuator switch

TECHNICAL DESCRIPTION (COMMENT)
Is the dome lights do not dim normally, the input circuits from the switches described in "CIRCUIT OPERATION" or the ETACS-ECU may be defective.

TROUBLESHOOTING HINTS
- Malfunction of the key reminder switch
- Malfunction of the door switches
- Malfunction of the driver? door lock actuator switch
- Malfunction of the ETACS-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 front dome light and the rear dome light.
If the front dome light switch and the rear dome light switch are moved to the "door interlock position", the front dome light and the rear dome light should illuminate when either door is opened.

Q: Do the front dome light and the rear dome light illuminate normally?
Both the front dome light and the rear dome light illuminate normally.: Go to Step 2.
Neither the front dome light nor the rear dome light illuminates normally.: Refer to Inspection Procedure K-1 "Front dome light, rear dome light and luggage compartment light do not illuminate or go out normally."
Either the front dome light or the rear dome light illuminates normally.: Refer to Inspection Procedure K-2 "Front dome light, rear dome light or luggage compartment light do not illuminates or goes out normally."







STEP 2. Use scan tool to select "ECU CHECK" on the SWS monitor display.

Check the ETACS-ECU.

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. When the ignition switch is turned to the "LOCK" (OFF) position, scan tool MB991502 should show "OK" on the "ETACS ECU" menu.

Q: Is "OK" displayed on the "ETACS ECU" menu?

YES: Go to STEP 3.

NO: Refer to Inspection Procedure A-3 "Communication with ETACS-ECU is impossible."

STEP 3. Check the input signal by using service data of the SWS monitor.







Check the input signals from the following switches:
- ignition switch: ON or START
- Driver's door: open




Select "ETACS ECU" (DATALIST), and check that normal conditions are displayed on the items described in the table.

Q: Are normal conditions displayed on the "IG SW (IG1)" and "FRONT DOOR SW"?

YES: Go to STEP 4.

NO:
- 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."

STEP 4. Check the input signal (by using the Pulse check).

Check the following switches and input signals:
- Key reminder switch
- All door switches
- interior light loaded signal







- If the switches (see table), which are applicable for the input signal check, are operated, check if scan tool MB991502 sounds or not.

Q: When the key reminder switch, each door switch and the interior light are operated, does scan tool MB991502 sound in each case?

YES: Replace the ETACS-ECU. Check that the dome light illuminates normally.

NO:
- Scan tool MB991502 does not sound when the ignition key is removed and reinserted.: Refer to Inspection Procedure M-1 "ETACS-ECU does not receive a signal from the key reminder switch."
- When one of the doors is opened and closed, scan tool MB991502 does not sound: Refer to Inspection Procedure M-4 "ETACS-ECU does not receive a signal from all the door switches." -When one of the interior lights is illuminated, scan tool MB991502 does not sound: Refer to Inspection Procedure M-11 "ETACS-ECU does not receive any multi-purpose fuse No. 17 loaded signal."