Page 385 of 1500

SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-385
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
Interior lamp loaded signal
(1) Operate diagnostic 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) When the switches (see table below), which are applicable
for the input signal check, are operated, check if diagnostic
tool MB991958 sounds or not.
Q: When the key reminder switch and the interior lamp are
operated, does diagnostic tool MB991958 sound in each
case?
Buzzer of diagnostic tool MB991958 sounds normally. :
Go to Step 4.
When the ignition key is removed and reinserted,
diagnostic tool MB991958 does not sound : Refer to
Inspection Procedure N-1 "ETACS-ECU does not
receive any signal from the key reminder switch
P.54B-432."
When one of the interior lamps is illuminated,
diagnostic tool MB991958 does not sound : Refer to
Inspection Procedure N-9 "ETACS-ECU does not
receive any interior lamp loaded signal P.54B-474."
STEP 4. Check ETACS-ECU connector C-218 for loose,
corroded or damaged terminals, or terminals pushed back
in the connector.
Q: Is ETACS-ECU connector C-218 in good condition?
YES : Go to Step 5.
NO : Repair or replace the damaged component(s). Refer
to GROUP 00E, Harness Connector Inspection
P.00E-2. Verify that the ignition key hole illumination
lamp illuminates normally. ITEM NAME CONDITION
key reminder switch Remove and reinsert the
ignition key
interior lamp loaded signal Turn on one of the interior
lamps
Page 389 of 1500

SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-389
STEP 11. Check the wiring harness between key reminder
switch connector C-310 (terminal 1) and ETACS-ECU
connector C-218 (terminal 63).
Q: Is the wiring harness between key reminder switch
connector C-310 (terminal 1) and ETACS-ECU connector
C-218 (terminal 63) in good condition?
YES : No action is necessary and testing is complete.
NO : The wiring harness may be damaged or the
connector(s) may have loose, corroded or damaged
terminals, or terminals pushed back in the connector.
Repair the wiring harness as necessary. Verify that
the ignition key hole illumination lamp illuminates
normally.
INSPECTION PROCEDURE K-5: Interior Light: The interior lamp automatic shutoff function does not
work normally.
NOTE: This troubleshooting procedure requires the
use of diagnostic tool MB991958 and SWS monitor
kit MB991813. For details on how to use the SWS
monitor, refer to "How to connect SWS monitor
P.54B-13."
.
CIRCUIT OPERATION
The ETACS-ECU operates the interior lamp auto-
matic shutdown function according to the following
switch signals:
Ignition switch (ACC)
Ignition switch (IG1)
Front door switch (LH)
Door switches
interior lamp loaded signal
.
TECHNICAL DESCRIPTION (COMMENT)
If the function does not work normally, the input cir-
cuit system from the switches or the ETACS-ECU
may be defective (refer to "CIRCUIT OPERATION").
.
TROUBLESHOOTING HINTS
Refer to circuit diagrams GROUP-90
Refer to configuration diagrams GROUP-80
Trouble in input signal system
The wiring harness or connectors may have
loose, corroded, or damaged terminals, or termi-
nals pushed back in the connector
The ETACS-ECU may be defective
Page 390 of 1500

SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-390
DIAGNOSIS
Required Special Tools:
MB991223: Harness Set
MB991958: Diagnostic Tool (MUT-III Sub Assembly)
MB991824: Vehicle Communication Interface (V.C.I.)
MB991827: MUT-III USB Cable
MB991910: MUT-III Main Harness A
MB991813: SWS Monitor Kit
MB991806: SWS Monitor Cartridge
MB991812: SWS Monitor Harness (For Column-ECU)
MB991822: Test Probe Harness
STEP 1. Check the interior lamps.
If the interior lamp switch is moved to the "door interlock posi-
tion", the interior lamps should illuminate when either door is
opened.
Q: Do the interior lamp illuminate normally?
All the interior lamps illuminate normally. : Go to Step 2.
None of the interior lamps illuminate normally. : Refer to
Inspection Procedure K-1 "The dome lamp do not
illuminate and go out normally P.54B-359."
Some of the interior lamps do not illuminate normally. :
Refer to Inspection Procedure K-2 "The front dome
lamp, rear dome lamp or trunk lamp do not illuminate
or go out normally P.54B-366."
STEP 2. Check the adjustment function.
Q: Has a setting other than "No auto-shutoff" been
selected for the interior lamp automatic shutdown
function by the adjustment function?
YES : Go to Step 3.
NO : Set the interior lamp automatic shutdown function to
another setting other than "No auto-shutoff".
Page 391 of 1500

SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-391
STEP 3. Use diagnostic tool MB991958 to select "ECU
COMM Check" on the SWS monitor display.
Check the ETACS-ECU.
To prevent damage to diagnostic tool MB991958, always
turn the ignition switch to the "LOCK" (OFF) position
before connecting or disconnecting diagnostic tool
MB991958. Connect special tool MB991910 before con-
necting 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 P.54B-13."
(2) Turn the ignition switch to the "LOCK" (OFF) position.
(3) Operate diagnostic 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) Diagnostic tool MB991958 should show "OK" on the "ECU
COMM Check" menu for the "ETACS ECU" menu.
Q: Is "OK" displayed for the "ETACS ECU" menu?
YES : Go to Step4.
NO : Refer to Inspection Procedure A-3 "Communication
with the ETACS-ECU is not possible P.54B-74."
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SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-392
STEP 4. Check the input signal by using "DATA LIST"
menu of the SWS monitor.
Check the input signals from the following switches:
Ignition switch: OFF
Driver’s or front passenger’s door: open
(1) Operate diagnostic 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 below.
Q: Does the diagnostic tool MB991958 display the items
"IG SW (IG1)", "IG SW (ACC)" and "FRONT DOOR SW"
as normal condition?
Normal conditions are displayed for all the items : Go to
St e p 5 .
Normal condition is not displayed for "IG SW (IG1)" :
Refer to Inspection Procedure M-2 "ETACS-ECU
does not receive any signal from the ignition switch
(IG1) P.54B-408."
Normal condition is not displayed for "IG SW (ACC)" :
Refer to Inspection Procedure M-1 "ETACS-ECU
does not receive any signal from the ignition switch
(ACC) P.54B-405."
Normal condition is not displayed for "FRONT DOOR
SW" : Refer to Inspection Procedure M-4 "ETACS-ECU
does not receive any signal from the front door
switches P.54B-413." ITEM NO. ITEM NAME NORMAL CONDITION
ITEM 30 IG SW (IG1) OFF
ITEM 31 IG SW (ACC) OFF
ITEM 32 FRONT DOOR SW ON
Page 393 of 1500

SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-393
STEP 5. Check the input signal (by using the pulse check
mode of the monitor).
Check the following switches and input signals:
Door switches
Interior lamp loaded signal
(1) Operate diagnostic 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 diagnostic tool MB991958 sounds or not.
Q: When any door switch, interior lamp or the trunk lid
latch is operated, does diagnostic tool MB991958
sound?
Buzzer of diagnostic tool MB991958 sounds normally. :
Replace the ETACS-ECU. Verify that the dome lamp
illuminates normally.
When one of the doors is opened and closed,
diagnostic tool MB991958 does not sound : Refer to
Inspection Procedure N-3 "ETACS-ECU does not
receive any signal from any of the door switches
P.54B-440."
When one of the interior lamps is illuminated,
diagnostic tool MB991958 does not sound : Refer to
Inspection Procedure N-9 "ETACS-ECU does not
receive any interior lamp loaded signal P.54B-474." ITEM NAME CONDITION
interior lamp loaded
signalTurn on one of the interior lamps
door switch Open or close one of the doors
Page 394 of 1500

SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-394
INSPECTION PROCEDURE K-6: Interior Light: The door ajar indicator lamps do not illuminate or go
out normally
NOTE: This troubleshooting procedure requires the
use of diagnostic tool MB991958 and SWS monitor
kit MB991813. For details on how to use the SWS
monitor, refer to "How to connect SWS monitor
P.54B-13."
.
CIRCUIT OPERATION
The combination meter receives the door switches
signals from the ETACS-ECU, and then controls the
door ajar indicator, based on these signals.
.
TECHNICAL DESCRIPTION (COMMENT)
If the door ajar indicator does not illuminate, connec-
tor(s), wiring harness in the CAN bus lines, the door
switches, the ETACS-ECU, or the combination meter
may be defective.
.
TROUBLESHOOTING HINTS
Refer to circuit diagrams GROUP-90
Refer to configuration diagrams GROUP-80
Trouble in input signal system
The wiring harness or connectors may have
loose, corroded, or damaged terminals, or termi-
nals pushed back in the connector
The combination meter may be defective
The ETACS-ECU may be defective
DIAGNOSIS
Required Special Tools:
MB991223: Harness Set
MB991958: Diagnostic Tool (MUT-III Sub Assembly)
MB991824: Vehicle Communication Interface (V.C.I.)
MB991827: MUT-III USB Cable
MB991910: MUT-III Main Harness A
MB991813: SWS Monitor Kit
MB991806: SWS Monitor Cartridge
MB991812: SWS Monitor Harness (For Column-ECU)
MB991822: Test Probe Harness
Page 395 of 1500

SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-395
STEP 1. Using diagnostic tool MB991958, diagnose the
CAN bus line.
To prevent damage to diagnostic tool MB991958, always
turn the ignition switch to the "LOCK" (OFF) position
before connecting or disconnecting diagnostic tool
MB991958.
(1) Connect diagnostic tool MB991958.Refer to "How to
connect SWS monitor P.54B-13."
(2) Turn the ignition switch to the "ON" position.
(3) Diagnose the CAN bus line.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the CAN bus line found to be normal?
YES : Go to Step 2.
NO : Repair the CAN bus line (Refer to GROUP 54C,
Diagnosis P.54C-15).
STEP 2. Using diagnostic tool MB991958, read the
combination meter diagnostic trouble code.
(1) Check whether the combination meter-related DTC is set.
(2) Turn the ignition switch to the "ON" position.
(3) Check whether the combination meter-related DTC is set.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the DTC set?
YES : Diagnose the combination meter. Refer to P.54A-48.
NO : Go to Step 3.