Page 308 of 1500

SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-308
(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."
Normal condition is not displayed for "H/L AUTO-CUT" :
Replace the front-ECU. Check that the headlamp
automatic shutdown function works normally.
INSPECTION PROCEDURE H-10: Headlamp and Taillamp: Headlamp dimmer switch automatic
resetting function does not work normally.
.
CIRCUIT OPERATION
The headlamp dimmer switch automatic resetting
function is controlled by the front-ECU.
.
TECHNICAL DESCRIPTION (COMMENT)
If the headlamp dimmer switch automatic resetting
function does not work normally, the front-ECU may
be defective.
.
TROUBLESHOOTING HINT
Refer to circuit diagrams GROUP-90
Refer to configuration diagrams GROUP-80
The front-ECU may be defective
DIAGNOSIS
Replace the front-ECU.
Check that the headlamp dimmer switch automatic resetting
function works normally.
Page 339 of 1500

SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-339
FOG LAMP
GENERAL DESCRIPTION CONCERNING THE FOG LAMPSM1549021400216
Refer to circuit diagrams GROUP-90
Refer to configuration diagrams GROUP-80The following ECUs affect the functions and control
of the fog lamps.
Fog lamp
The fog lamps will illuminate only when the fog lamp
switch is operated while the low-beam headlamps
are on.
The fog lamps will be switched off when any of the
following conditions is met. The fog lamps will also
be switched off automatically by headlamp automatic
shutoff function.
When the high-beam headlamps are switched
on, the fog lamps will be switched off. If the
low-beam headlamps are switched on again, the
fog lamps will illuminate again.
When the headlamp switch is turned off or the tail
lamps and headlamps are off, the fog lamps will
be switched off. If the low-beam headlamps are
switched on again, the fog lamps will not illumi-
nate again.
Fog lamp indicator
At the same time that the fog lamps are illuminated, the
ETACS-ECU sends a signal to illuminate the fog lamp indicator
via the CAN bus line. The combination meter receives the
transmitted signal and turns the fog lamp indicator on and off. FUNCTION CONTROL ECU
Fog lamp ETACS-ECU, front-ECU, column switch
Fog lamp indicator ETACS-ECU, column switch
Page 340 of 1500

SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-340
INSPECTION PROCEDURE J-1: Fog Light: Fog lamps do not illuminate when the fog lamp switch is
turned on.
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 sends a fog lamp illumination
request signal ("LAMP ON" signal) to the
front-ECU when the fog lamp switch is turned on
while the headlamps are illuminating at low
beam.
Then the front-ECU switches on its relay to illumi-
nate the fog lamps.
.
TECHNICAL DESCRIPTION (COMMENT)
If the headlamps illuminate at low beam, the fog
lamp relay, the fog lamp switch, the front-ECU 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 fog lamp relay may be defective
The front-ECU 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
STEP 1. Check the headlamp (low-beam) operation.
Q: Do the headlamps illuminate at low beam normally?
YES : Go to Step 2.
NO : Refer to Inspection Procedure H-2 "The headlamps
(low-beam) do not illuminate normally P.54B-264."
Page 341 of 1500

SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-341
STEP 2. Check the input signal by using "FUNCTION
DIAG." menu of the SWS monitor.
Set each switch to the following condition before checking input
signal from the fog lamp switch:
Ignition switch: ON
Fog lamp switch: ON
NOTE: Turn the ignition switch to the "ON" position in order to
disable the headlamp automatic shutdown function.
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) Operate Diagnostic Tool MB991958 according to the
procedure below to display "F.FOG."
a. Select "Interactive Diagnosis."
b. Select "System select."
c. Select "SWS."
d. Select "SWS MONITOR."
e. Select "Function Diag."
f. Select "LIGHTING."
g. Select "F.FOG."
(3) 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 "F.FOG LAMP" 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 "F.FOG LAMP" :
Refer to Inspection Procedure M-3 "ETACS-ECU
does not receive any signal from the fog lamp switch
P.54B-410." ITEM NO. ITEM NAME NORMAL CONDITION
ITEM 30 IG SW (IG1) ON
ITEM 36 F.FOG LAMP ON
Page 345 of 1500

SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-345
INSPECTION PROCEDURE J-2: Fog Light: Fog lamps do not go out when the headlamps (low-beam)
are turned off while the fog lamps are on.
.
TECHNICAL DESCRIPTION (COMMENT)
If the trouble above occurs, the front-ECU may be
defective.
.
TROUBLESHOOTING HINT
Refer to circuit diagrams GROUP-90
Refer to configuration diagrams GROUP-80
The front-ECU may be defective
DIAGNOSIS
Replace the front-ECU.
The fog lamps should go out when the headlamps (low-beam)
are turned off while the fog lamps are on.
INSPECTION PROCEDURE J-3: Fog Light: One of the fog lamps does not illuminate.
.
TECHNICAL DESCRIPTION (COMMENT)
If one of the fog lamps does not illuminate, the fog
lamp relay or the fog lamp bulb may be defective. If
the fog lamp indicator lamp does not illuminate, the
combination meter may be defective.
.
TROUBLESHOOTING HINTS
Refer to circuit diagrams GROUP-90
Refer to configuration diagrams GROUP-80
The wiring harness or connectors may have
loose, corroded, or damaged terminals, or termi-
nals pushed back in the connector
The fog lamp bulb may be defective
.
DIAGNOSIS
Required Special Tool:
MB991223: Harness Set
Page 408 of 1500

INPUT SIGNAL PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-408
INSPECTION PROCEDURE M-2: ETACS-ECU does not receive any signal from the ignition switch
(IG1).
.
CIRCUIT OPERATION
The ETACS-ECU operates the following equipment
or functions according to signal from the ignition
switch (IG1):
Light reminder tone alarm function
Seat belt tone alarm function
Door ajar warning buzzer
Turn-signal lamp buzzer
Multi center display operation tone
multi center display (middle grade type)>
Power window timer function
Sunroof timer function
Headlamp automatic shutdown function
Turn-signal lamp
Dome lamp dimming function
Ignition key hole illumination lamp
If the power supply circuit from the battery to the
ETACS-ECU is open, this circuit is used as
backup circuit.
If the signal is not normal, the equipment or functions
described in "CIRCUIT OPERATION" do not work
normally.
The ETACS-ECU receives information on the ignition
switch condition (IG1) from the combination meter
via CAN communication. If the ignition switch (IG1)
input signal is incorrect, refer to the Diagnostic Trou-
ble Code Chart P.54B-25.
.
TROUBLESHOOTING HINTS
Refer to circuit diagrams GROUP-90
Refer to configuration diagrams GROUP-80
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
DIAGNOSIS
Required Special Tool:
MB991223: Harness Set
STEP 1. Check ETACS-ECU connector C-219 for loose,
corroded or damaged terminals, or terminals pushed back
in the connector.
Q: Is ETACS-ECU connector C-219 in good condition?
YES : Go to Step 2.
NO : Repair or replace the damaged component(s). Refer
to GROUP 00E, Harness Connector Inspection
P.00E-2. If the functions described in "CIRCUIT
OPERATION" work normally, the input signal from the
ignition switch (IG1) should be normal.
Page 414 of 1500

INPUT SIGNAL PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-414
CIRCUIT OPERATION
The ETACS-ECU operates the following functions or
systems according to signal from the front door
switches:
Light reminder tone alarm function
switch (RH)>
Door ajar warning buzzer
Forgotten key reminder
Power window timer function
Sunroof timer function
Keyless entry system
Timed locking mechanism
Headlamp automatic shutdown function
door switch (RH)>
Dome lamp
Interior lamp automatic-shutdown function
Ignition key hole illumination lamp
switch (RH)>
Door-ajar indicator lamp
.
TECHNICAL DESCRIPTION (COMMENT)
If the signal is not normal, the functions or systems
described in "CIRCUIT OPERATION" do not work
normally. If the signal is not normal, the front door
switches or the ETACS-ECU may be defective.
.
TROUBLESHOOTING HINTS
Refer to circuit diagrams GROUP-90
Refer to configuration diagrams GROUP-80
The front door switches may be defective
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 420 of 1500

INPUT SIGNAL PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-420
INSPECTION PROCEDURE M-5: Column Switch: ETACS-ECU does not receive any signal from the
taillamp switch, the headlamp switch, the passing lamp switch, the dimmer switch or the turn-signal
lamp switch.
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 following equipment
or functions according to signal from the column
switch (turn-signal lamp and lighting switch):
Light reminder tone alarm function
Turn-signal lamp buzzer
Headlamp
Turn-signal lamp
High-beam indicator
Turn-signal indicators
.
TECHNICAL DESCRIPTION (COMMENT)
If the signal is not normal, the equipment or functions
described in "CIRCUIT OPERATION" do not work
normally. If the signal is not normal, the column
switch (turn-signal lamp and lighting switch) or the
ETACS-ECU may be defective.
.
TROUBLESHOOTING HINTS
Refer to circuit diagrams GROUP-90
Refer to configuration diagrams GROUP-80
The column switch (turn-signal lamp and lighting
switch) 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