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
Page 421 of 1500

INPUT SIGNAL PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-421
STEP 1. Use diagnostic tool MB991958 to select "ECU
COMM Check" on the SWS monitor display.
Check the column-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 "ON" position.
(3) Operate the diagnostic tool 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 (MUT-III) should show "OK" on the "ECU
COMM Check" menu for the "COLUMN ECU" menu.
Q: Is "OK" displayed for the "COLUMN ECU" menu?
YES : Go to Step 2.
NO : Refer to Inspection Procedure A-2 "Communication
with the column switch (column-ECU) is not possible
P.54B-68."
Page 422 of 1500

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
Page 423 of 1500

INPUT SIGNAL PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-423
INSPECTION PROCEDURE M-6: Column switch: ETACS-ECU does not receive any signal from the
windshield mist wiper switch, the windshield intermittent wiper switch, the windshield low-speed
wiper switch, the windshield high-speed wiper switch or the windshield washer 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 windshield wiper and
washer according to signal from the windshield wiper
and washer switch.
.
TECHNICAL DESCRIPTION (COMMENT)
If the signal is not normal, the windshield wiper and
washer do not work normally.
.
TROUBLESHOOTING HINTS
Refer to circuit diagrams GROUP-90
Refer to configuration diagrams GROUP-80
The column switch may be defective (windshield
wiper and washer switch)
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 424 of 1500

INPUT SIGNAL PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-424
STEP 1. Use diagnostic tool MB991958 to select "ECU
COMM Check" on the SWS monitor display.
Check the column-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 "ON" position.
(3) Operate the diagnostic tool 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 (MUT-III) should show "OK" on the "ECU
COMM Check" menu for the "COLUMN ECU" menu.
Q: Is "OK" displayed for the "COLUMN ECU" menu?
YES : Go to Step 2.
NO : Refer to Inspection Procedure A-2 "Communication
with the column switch (column-ECU) is not possible
P.54B-68."
Page 425 of 1500

INPUT SIGNAL PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-425
STEP 2. Check the windshield wiper and washer switch.
Remove the windshield wiper and washer switch. Then check
continuity between the switch terminals.
Q: Are the windshield wiper and washer switch in good
condition?
YES : Go to Step 3.
NO : Replace the windshield wiper and washer switch. If
the equipment described in "CIRCUIT OPERATION"
work normally, the input signal from the column switch
(windshield wiper and washer switch) should be
normal.
STEP 3. Replace the column switch.
(1) Replace the column switch.
(2) If the equipment described in "CIRCUIT OPERATION" work
normally, the input signal from the column switch
(windshield wiper and washer switch) should be normal.
Q: Does the column switch (windshield wiper and washer
switch) send a normal signal to the ECU?
YES : No action is necessary and testing is complete.
NO : Replace the ETACS-ECU. If the equipment described
in "CIRCUIT OPERATION" work normally, the input
signal from the column switch (windshield wiper and
washer switch) should be normal. SWITCH
POSITIONTESTER
CONNECTIONSPECIFIED
CONDITION
OFF 21
23, 22 23, 23
30, 23
31, 23 32,
25
26, 25 29Open circuit
Windshield mist
wiper switch23
32 Less than 2 ohms
Windshield
intermittent wiper
switch23
31 Less than 2 ohms
Windshield
low-speed wiper
switch23
30 Less than 2 ohms
Windshield
high-speed wiper
switch21
23 Less than 2 ohms
Windshield washer
switch22
23 Less than 2 ohms
Page 426 of 1500

INPUT SIGNAL PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-426
INSPECTION PROCEDURE M-7: Column Switch: ETACS-ECU does not receive any signal from the
variable intermittent wiper control switch.
.
CIRCUIT OPERATION
The ETACS-ECU calculates the windshield intermit-
tent wiper interval according to the position of the
variable intermittent wiper control switch, which is
incorporated in column switch (windshield wiper and
washer switch).
.
TECHNICAL DESCRIPTION (COMMENT)
If the windshield intermittent wiper interval cannot be
adjusted, the column 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 may be defective (windshield
wiper and washer switch)
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 column switch connector C-309 for loose,
corroded or damaged terminals, or terminals pushed back
in the connector.
Q: Is column switch connector C-309 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 wiper interval can be adjusted
normally, the variable intermittent wiper control switch
should send a signal to the ECU.
Page 427 of 1500

INPUT SIGNAL PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-427
STEP 2. Check the variable intermittent wiper control
switch.
(1) Remove the windshield wiper and washer switch, and
check at the switch side.
(2) Measure the resistance value between terminals 27 and 28.
The measured resistance should change smoothly from
approximately 0 ohm ("FAST" position) to 1 k
("SLOW"
position).
Q: Is the variable intermittent wiper control switch in good
condition?
YES : Go to Step 3.
NO : Replace the column switch (windshield wiper and
washer switch). If the wiper interval can be adjusted
normally, that the variable intermittent wiper control
switch should send a signal to the ECU.
STEP 3. 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 4.
NO : Repair or replace the damaged component(s). Refer
to GROUP 00E, Harness Connector Inspection
P.00E-2. If the wiper interval can be adjusted
normally, that the variable intermittent wiper control
switch should send a signal to the ECU.