Page 404 of 1500

SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-404
STEP 3. Use diagnostic tool MB991958 to select "ECU
COMM Check" on the SWS monitor display.
Check the ETACS-ECU.
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 SWS monitor. Refer to "How to connect SWS
monitor P.54B-13."
(2) Turn the ignition switch to the "ON" 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 4.
NO : Refer to Inspection Procedure A-3 "Communication
with the ETACS-ECU is not possible P.54B-74."
STEP 4. Replace the multi center display .
(1) Replace the multi center display .
(2) Check if it is possible to customise the functions by
operating the new multi center display .
Q: Is it possible to customise the functions by operating
the multi center display ?
YES : No action is necessary and testing is complete.
NO : Replace the ETACS-ECU. Verify that it is possible to
customise the functions by operating the multi center
display .
Page 405 of 1500

INPUT SIGNAL PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-405
INPUT SIGNAL PROCEDURES
INSPECTION PROCEDURE M-1: ETACS-ECU does not receive any signal from the ignition switch
(ACC).
.
CIRCUIT OPERATION
The ETACS-ECU operates the following equipment
and function(s) according to signal from the ignition
switch (ACC):
Windshield wiper and washer
Interior lamp automatic shutoff function
The ETACS-ECU receives information on the ignition
switch condition (ACC) from the middle-grade multi
center display unit via CAN communication. If the
ignition switch (ACC) input signal is incorrect, refer to
the appropriate Diagnostic Trouble Code Chart
P.54B-25.
.
TECHNICAL DESCRIPTION (COMMENT)
If the signal is not normal, the equipment and func-
tion(s), which are described in "CIRCUIT OPERA-
TION", do not work normally.
.
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
Page 406 of 1500

INPUT SIGNAL PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-406
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 equipment described in "CIRCUIT
OPERATION" works normally, the input signal from
the ignition switch (ACC) should be normal.
STEP 2. Check the ignition switch (ACC) line of the power
supply circuit to the ETACS-ECU. Measure the voltage at
ETACS-ECU connector C-219.
(1) Disconnect ETACS-ECU connector C-219 and measure the
voltage available at the junction block side of the connector.
(2) Turn the ignition switch to the "ACC" position.
(3) Measure the voltage between terminal 4 and ground.
The voltage should measure approximately 12 volts
(battery positive voltage).
Q: Is the measured voltage approximately 12 volts (battery
positive voltage)?
YES : Replace the ETACS-ECU. If the equipment described
in "CIRCUIT OPERATION" works normally, the input
signal from the ignition switch (ACC) should be
normal.
NO : Go to Step 3.
Page 407 of 1500

INPUT SIGNAL PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-407
STEP 3. Check the wiring harness between ETACS-ECU
connector C-219 (terminal 4) and the ignition switch (ACC).
NOTE: Also check intermediate connector C-29 and junction
block connector C-214 for loose, corroded, or damaged termi-
nals, or terminals pushed back in the connector. If intermediate
connector C-29 or junction block connector C-214 is damaged,
repair or replace the damaged component(s) as described in
GROUP 00E, Harness Connector Inspection P.00E-2.
Q: Is the wiring harness between ETACS-ECU connector
C-219 (terminal 4) and ignition switch (ACC) 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. If the
equipment described in "CIRCUIT OPERATION"
works normally, the input signal from the ignition
switch (ACC) should be normal.
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 409 of 1500
INPUT SIGNAL PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-409
STEP 2. Check the ignition switch (IG1) line of the power
supply circuit to the ETACS-ECU. Measure the voltage at
ETACS-ECU connector C-219.
(1) Disconnect ETACS-ECU connector C-219 and measure the
voltage available at the junction block side of the connector.
(2) Turn the ignition switch to the "ON" position.
(3) Measure the voltage between terminal 8 and ground.
The voltage should measure approximately 12 volts
(battery positive voltage).
Q: Is the measured voltage approximately 12 volts (battery
positive voltage)?
YES : Replace the ETACS-ECU. If the functions described
in "CIRCUIT OPERATION" work normally, the input
signal from the ignition switch (IG1) should be normal.
NO : Go to Step 3.
STEP 3. Check the wiring harness between ETACS-ECU
connector C-219 (terminal 8) and the ignition switch (IG1).
Page 410 of 1500
INPUT SIGNAL PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-410
NOTE: Also check junction block connector C-215 for loose,
corroded, or damaged terminals, or terminals pushed back in
the connector. If junction block connector C-215 is damaged,
repair or replace the damaged component(s) as described in
GROUP 00E, Harness Connector Inspection P.00E-2.
Q: Is the wiring harness between ETACS-ECU connector
C-219 (terminal 8) and ignition switch (IG1) 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. If the
functions described in "CIRCUIT OPERATION" work
normally, the input signal from the ignition switch
(IG1) should be normal.
INSPECTION PROCEDURE M-3: ETACS-ECU does not receive any signal from the fog lamp switch.
.
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