Inspection Procedure M-1

Interior Light: Dome Light, Luggage Compartment Light , Trunk Light and Door-ajar Indicator Light does not Illuminate or Turn off Normally.

Interior Light Automatic Shut-down Function Circuit:

NOTE: This troubleshooting procedure requires the use of scan tool MB991958 and SWS monitor kit MB991813. For details on how to use the SWS monitor, refer to "How to use SWS monitor." How To Use SWS Monitor

CIRCUIT OPERATION
The ETACS-ECU illuminates the dome light, the luggage compartment light and the trunk light according to the following signals:
- Ignition switch (IG1): ON or OFF
- Key reminder switch: ON or OFF
- Front door switch: ON or OFF
- Driver's door lock actuator switch: ON or OFF
- Liftgate latch switch (vehicles with theft-alarm system) or liftgate light switch (vehicles without theft-alarm system): ON or OFF
- Trunk lid latch switch (vehicles with theft-alarm system) or trunk light switch (vehicles without theft-alarm system): ON or OFF
- Interior light loaded signal: ON

TECHNICAL DESCRIPTION (COMMENT)
If the dome light, the luggage compartment light and trunk light do not illuminate normally, the dome light bulb(s) may be burned out or the input circuit system from the switches, the power supply lines to the switches or the ETACS-ECU may be defective (refer to "CIRCUIT OPERATION").

TROUBLESHOOTING HINTS
- The key reminder switch may be defective
- The door switch may be defective
- The driver's door lock actuator switch may be defective
- The dome light may be defective
- The liftgate latch switch or liftgate light switch may be defective
- The trunk lid switch or trunk light switch may be defective
- The ETACS-ECU may be defective
- The wiring harness or connectors may have loose, corroded, or damaged terminals, or terminals pushed back in the connector

DIAGNOSIS

Required Special Tools:
- MB991223: Harness Set
- MB991958: Scan Tool (MUT-III Sub Assembly)
- MB991824: Vehicles communication interface (V.C.I.)
- MB991827: MUT-III USB cable
- MB991911: MUT-III Main harness B
- MB991813: SWS monitor kit
- MB991806: SWS monitor cartridge
- MB991812: SWS monitor harness (for column-ECU)
- MB991922: Probe harness

STEP 1. Use scan tool MB991958 to select "ECU COMM CHK" on the SWS monitor display.
Check the ETACS-ECU.

CAUTION: To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958. Connect special tool MB991910 before connecting special tool MB991812. Be sure to connect special tool MB991806 after turning on special tool MB991824.

1. Connect the special tool. Refer to "How to connect SWS monitor." How to Connect SWS Monitor
2. Turn the ignition switch to the "LOCK" (OFF) position.
3. Operate scan tool MB991958 according to the procedure below to display "ECU COMM Check."
a. Select "Interactive Diagnosis."
b. Select "System select."
c. Select "SWS."
d. Select "SWS MONITOR."
e. Select "ECU COMM Check."

4. Scan tool MB991958 should show "OK" on the "ECU COMM Check" menu for the "ETACS ECU" menu.

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

YES: Go to Step 2.

NO: Refer to Inspection Procedure A-3 "Communication with ETACS-ECU is not possible."

STEP 2. Check the input signal by using "DATA LIST" menu of the SWS monitor.
Check the input signals from the following switches:
- Ignition switch: ON or START
- Driver's or front passenger's door: open

1. Operate scan tool MB991958 according to the procedure below to display "ETACS ECU."
a. Select "Interactive Diagnosis."
b. Select "System select."
c. Select "SWS."
d. Select "SWS MONITOR."
e. Select "Data List."
f. Select "ETACS ECU."

2. Check that normal conditions are displayed for the items described in the table.

Q: Does scan tool MB991958 display the items "IG SW (IG1)" and "FRONT DOOR SW" as normal condition?

Normal conditions are displayed for all the items: Go to Step 3.
Normal condition is not displayed for "IG SW (IG1)": Refer to Inspection Procedure O-2 "ETACS-ECU does not receive a signal from the ignition switch (IG1)."
Normal condition is not displayed for "FRONT DOOR SW": Refer to Inspection Procedure O-6 "ETACS-ECU does not receive a signal from the driver's or the front passenger's door switch."

STEP 3. Check the input signal (by using the Pulse check mode of the monitor).
Check the following switches and input signals:
- Key reminder switch
- Liftgate latch switch or liftgate light switch
- Trunk lid latch switch or trunk light switch
- interior light loaded signal

1. Operate scan tool MB991958 according to the procedure below to display "Pulse check."
a. Select "Interactive Diagnosis."
b. Select "System select."
c. Select "SWS."
d. Select "Pulse Checking."

2. Check if scan tool MB991958 sounds or not.

Q: When the key reminder switch, liftgate latch switch or liftgate light switch , and the trunk lid latch switch or trunk light switch and the interior light loaded signal is operated, does scan tool MB991958 sound in each case?

Normal conditions are displayed for all the items: Replace the ETACS-ECU. Verify that the dome light illuminates normally.
Scan tool MB991958 does not sound when the ignition key is removed and reinserted: Refer to Inspection Procedure P-1 "ETACS-ECU does not receive a signal from the key reminder switch."
When the liftgate or trunk lid is opened and closed, scan tool MB991958 does not sound: Refer to Inspection Procedure P-9 "ETACS-ECU does not receive a signal from the liftgate latch switch or trunk lid latch switch ."
When one of the interior lights is illuminated, scan tool MB991958 does not sound: Refer to Inspection Procedure P-14 "ETACS-ECU does not receive a interior light loaded signal."