SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-398
INSPECTION PROCEDURE K-7: Interior Light: The seat belt warning lamp 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 and the ETACS-ECU illumi-
nates and flashes the seat belt warning lamp by
using the signal from the seat belt switch, the ignition
switch (IG1) and the vehicle speed signal.
.
TECHNICAL DESCRIPTION (COMMENT)
If the seat belt warning lamp does not illuminate or
flash correctly, connector(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
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
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.
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
Door ajar warning buzzer
Forgotten key reminder
Power window timer function
Sunroof timer function
Keyless entry system
Timed locking mechanism
Headlamp automatic shutdown function
Dome lamp
Interior lamp automatic-shutdown function
Ignition key hole illumination lamp
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
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
INPUT SIGNAL PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-422
STEP 2. Check the turn-signal lamp and lighting switch.
Remove the turn-signal lamp and the lighting switch. Then
check continuity between the switch terminals.
Q: Are the turn-signal lamp and lighting switch in good
condition?
YES : Go to Step 3.
NO : Replace the turn-signal lamp and the lighting switch.
The input signal from the column switch (turn-signal
lamp and lighting switch) should be able to be
checked and the functions described in the "CIRCUIT
OPERATION" should work normally.
STEP 3. Replace the column switch.
(1) Replace the column switch.
(2) The input signal from the column switch (turn-signal lamp
and lighting switch) should be able to be checked and the
functions described in the "CIRCUIT OPERATION" should
work normally.
Q: Is the input signal from the column switch (turn-signal
lamp and lighting switch) input normal?
YES : No action is necessary and testing is complete.
NO : Replace the ETACS-ECU. The input signal from the
column switch (turn-signal lamp and lighting switch)
should be able to be checked and the functions
described in the "CIRCUIT OPERATION" should work
normally. SWITCH
POSITIONTESTER
CONNECTIONSPECIFIED
CONDITION
OFF 1
2, 2 3, 2 11,
2
12, 5 9, 7 9Open circuit
Taillight switch 5
9 Less than 2 ohms
Headlamp switch5
9, 7 9 Less than 2 ohms
Passing switch 2
12 Less than 2 ohms
Dimmer switch 2
11, 2 12 Less than 2 ohms
Turn-signal lamp
switch (LH)1
2 Less than 2 ohms
Turn-signal lamp
switch (RH)2
3 Less than 2 ohms
INPUT SIGNAL PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-437
STEP 2. Check the hazard warning lamp switch.
Remove the hazard warning lamp switch. Refer to GROUP
54A, Hazard Warning Light Switch P.54A-168. Then check
continuity between the switch terminals.
Q: Is the hazard warning lamp switch in good condition?
YES : Go to Step 3.
NO : Replace the hazard warning lamp switch. If the
equipment described in "CIRCUIT OPERATION",
work normally the input signal from the hazard
warning lamp switch should be normal.
STEP 3. Check the ground circuit to the hazard warning
lamp switch. Measure the resistance at hazard warning
lamp switch connector C-08.
(1) Disconnect hazard warning lamp switch connector C-08
and measure the resistance available at the wiring harness
side of the connector.
(2) Measure the resistance value between terminal 2 and
ground.
The resistance should be 2 ohms or less.
Q: Is the measured resistance 2 ohms or less?
YES : Go to Step 5.
NO : Go to Step 4. SWITCH
POSITIONTESTER
CONNECTIONSPECIFIED
CONDITION
Released 1
2 Open circuit
Pressed 1
2 Less than 2 ohms
INPUT SIGNAL PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-440
INSPECTION PROCEDURE N-3: ETACS-ECU does not receive any signal from any of the door
switches.
.
CIRCUIT OPERATION
The ETACS-ECU operates the following functions or
systems according to signal from the front or rear
door switches:
Light reminder tone alarm function
Door ajar warning buzzer
Ignition key reminder tone alarm
Power window timer function
Sunroof timer function
Headlamp automatic shutdown function
Keyless entry system
Timer lock
Dome lamp
Interior lamp automatic-shutdown function
Ignition key hole illumination lamp
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 or rear
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 or rear 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
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
CHECK AT ECU TERMINAL
SIMPLIFIED WIRING SYSTEM (SWS)54B-484
FRONT-ECU
NOTE: Terminal voltages cannot be measured as the
front-ECU is installed directly on the relay box.
Therefore, this information is only for reference.
TERMINAL
NO.INSPECTION ITEM INSPECTION CONDITION NORMAL VALUE
1 Output to fog lamp relay When the fog lamps are on Battery positive voltage
2 Output to headlamp (high-beam) When headlights (high-beam)
are onBattery positive voltage
3, 4 Battery power supply (for
headlamp)Always Battery positive voltage
5 Battery power supply (for
taillamp)Always Battery positive voltage
6 Output to headlamp (low-beam) When headlights (low-beam) are
onBattery positive voltage
7 Battery power supply (for ECU) Always Battery positive voltage
8 Output to taillamps When taillamps are on Battery positive voltage
9
11
21 Output to windshield washer When windshield washer is on Battery positive voltage
22 SWS communication line Always 0
12 V (pulse signal)
23 Input of automatic stop signal to
windshield wiperWhen windshield wiper is on Battery positive voltage
24 Power supply to ignition switch
(ACC)Ignition switch: "ACC" Battery positive voltage
25 Input of backup signal from
headlamp switchHeadlamp switch: ON0 V
26 Input of backup signal to
windshield wiperWindshield low-speed wiper
switch or windshield high-speed
wiper switch: ON0 V
27 Output to windshield wiper
(low-speed)When windshield wiper is on (at
low speed)Battery positive voltage
28 Output to windshield wiper
(high-speed)When windshield wiper is on (at
high speed)Battery positive voltage
30 Power supply to ignition switch
(IG2)Ignition switch: "ON" Battery positive voltage
31 Ground Always 0 V