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SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-355
54B
INTERIOR LAMP
GENERAL DESCRIPTION CONCERNING THE INTERIOR LAMPM1549021800236
Refer to circuit diagrams GROUP-90
Refer to configuration diagrams GROUP-80The following ECUs affect the functions and control
of the interior lamps.
Interior lamp control function
The ETACS-ECU controls the interior lamps by turn-
ing them on and off in the following way:
When a door is opened with the ignition switch
off, the interior lamps up to a luminance of 100
percent. When a door is closed, the interior lamps
dims at a luminance of 65 percent, and goes off
30 seconds later. However if the ignition switch is
turned ON or if a door is locked while the interior
lamps is dimming, the dome lamp will go off at
that point.
When a door is opened with the ignition switch
ON, the interior lamps up at a luminance of 100
percent. When a door is closed, the interior lamps
go off.
When the ignition key is removed with all doors
closed, the interior lamps up at a luminance of
100 percent, and goes off 30 seconds later. How-
ever if the ignition key is inserted again or if a
door is locked while the interior lamps is lighting,
the interior lamps will go off at that point.
To check keyless entry operations more easily,
the interior lamps is flashed once when the doors
are locked. When the doors are unlocked, the
interior lamps at a luminance of 100 percent, and
go off 15 seconds later.
NOTE: The dimmer function can be customised on
vehicles equipped with a multi center display (middle
grade type). Refer to P.54B-486.
NOTE: The dotted lines indicate that lighting mode
when the ignition switch is turned ON, door is locked,
or any door is opened during the timer illumination
time. FUNCTION CONTROL ECU
Interior lamp control function ETACS-ECU
Interior lamp automatic-shutoff function ETACS-ECU
Ignition key hole illumination lamp function ETACS-ECU
Door ajar indicator ETACS-ECU
Seat belt indicator ETACS-ECU
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SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-356
Interior lamp automatic-shutoff function
Illuminated interior lamps such as the front dome
lamp, etc. (all lamps using the dome lamp fuse as the
power supply) will automatically go off in the follow-
ing conditions to prevent the battery from discharging
as a result of forgetting to turn off the lamps or
incomplete closing of the door.
When the ignition switch is turned off and more
than 30 minutes pass with the interior lamp illumi-
nated, the interior lamps will go off automatically.
When the ignition switch is turned off and one of
the door switches remains open for 30 minutes
continuously, the interior lamps will go off auto-
matically.
NOTE: The interior lamp automatic shutoff function
can be customised on vehicles equipped with a multi
center display (middle grade type). Refer to
P.54B-486.
Ignition key hole illumination lamp function
The ignition key hole illumination lamp illuminates when the
driver's door is opened with the ignition switch off, and for 30
seconds after the driver's door is closed. It also illuminates for
30 seconds after the ignition key is pulled out. In any case, it
goes out when the ignition switch is turned on.
Door ajar indicator
The combination meter receives the signal sent from the
ETACS-ECU about whether each door is open or closed and
turns the door ajar indicator on and off. While the door ajar indi-
cator is illuminated, the door ajar warning function is activated
and the door ajar indicator flashes 4 times. If the door remains
open even after the 4 warning flashes, the door ajar indicator
will be illuminated again. And when the interior lamp auto-
matic-shutoff function is activated, the door ajar indicator is
extinguished.
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SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-358
If any of the following conditions is met with the igni-
tion switch at "ON" or "ST", the ETACS-ECU illumi-
nates, flashes or extinguishes the seat belt indicator
by using the driver's seat belt switch signal and the
vehicle speed signal sent from the combination
meter.
Illuminates when the ignition switch is at "ON"
and the seat belt switch is turned on (the driver's
seat belt is unfastened).
Flashes and illuminates the indicator 12 cycles
(after 0.5 seconds) if any of the following condi-
tions is met when sixty seconds or more have
elapsed since the ignition switch is turned "ON".
One cycle consists of five-second "flashing" and
then three-second "illumination".a. The vehicle speed has reached 8 km/h (5
mph) while the seat belt switch is turned on
(driver's seat belt is not fastened) with the
ignition switch "ON.
b. The seat belt switch has been turned on
(driver's seat belt has not been fastened) for
at least ten seconds while the ignition switch
has been turned "ON" and the vehicle speed
has been 8 km/h (5 mph) or more.
NOTE: Once this timer operation has been acti-
vated, it will not be activated again until the
vehicle speed reduces to 3 km/h (2 mph) or
less even if any of the following conditions is
met.
The indicator stops illuminating if the ignition
switch or the seat belt switch is turned off (the
driver's seat belt is fastened) while the timer
operation is active.
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SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-359
INSPECTION PROCEDURE K-1: Interior Light: The dome lamp do not illuminate and 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 ETACS-ECU operates the dome lamp according
to the following signals:
Ignition switch (IG1): ON or OFF
Key reminder switch: ON or OFF
Door switches: ON or OFF
Driver’s door lock actuator switch: ON or OFF
Interior lamp loaded signal: ON
.
TECHNICAL DESCRIPTION (COMMENT)
If the dome lamp does not illuminate normally, a
burned-out dome lamp bulb, the input circuits from
the switches described in "CIRCUIT OPERATION",
the power supply line to the switches or the
ETACS-ECU 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 ETACS-ECU may be defective
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SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-360
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
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SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-361
STEP 1. 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 Step 2.
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-362
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 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)" and "FRONT DOOR SW" as normal
condition?
Normal conditions are displayed for all the items : Go to
St e p 3 .
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 "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) ON
ITEM 32 FRONT DOOR SW ON
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SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-363
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
Door switches
(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 the key reminder switch, any door switch or
interior lamp is operated, does diagnostic tool
MB991958 sound?
Buzzer of diagnostic tool MB991958 sounds normally. :
Go to Step 4.
Diagnostic tool MB991958 does not sound when the
ignition key is removed and reinserted : 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."
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." ITEM NAME CONDITION
key reminder switch Remove and reinsert the ignition
key
interior lamp loaded
signalTurn on one of the interior lamps
door switches Open or close one of the doors