Page 194 of 1500

SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-194
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
STEP 1. Verify the keyless entry system.
Q: Does the keyless entry system work normally?
YES : Go to Step 2.
NO : Refer to Inspection Procedure E-1 "Keyless entry
system does not operate P.54B-191."
STEP 2. Check the configuration function.
Q: Has the answerback function been enabled by means of
the adjustment function?
YES : Go to Step 3.
NO : Enable the answerback function by means of the
adjustment function. Verify that the answerback
functions work normally.
STEP 3. Verify trouble symptom.
Q: Which answerback function is defective?
Only the dome lamp : Go to Step 4.
Only the turn-signal lamps : Go to Step 5.
Only the horn : Go to Step 6.
Dome lamp, turn-signal lamps and horn : Replace the
ETACS-ECU. Verify that the answerback functions
work normally.
STEP 4. Verify the dome lamp.
Q: Does the dome lamp illuminate normally?
YES : Replace the ETACS-ECU. Verify that the answerback
functions work normally.
NO : Refer to Inspection Procedure K-1 "The dome lamp
do not illuminate and go out normally P.54B-359."
STEP 5. Verify the hazard warning lamp.
Q: Does the hazard warning lamp work normally?
YES : Replace the ETACS-ECU. Verify that the answerback
functions work normally.
NO : Refer to Inspection Procedure I-2 "Hazard warning
lamps do not flash when the hazard warning lamp
switch is turned on P.54B-314."
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SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-196
STEP 10. Check the wiring harness between horn relay
connector A-06X (terminal 4) and horn (HIGH) connector
A-37 (terminal 1).
Q: Is the wiring harness between horn relay connector
A-06X (terminal 4) and horn (HIGH) connector A-37
(terminal 1) in good condition?
YES : Replace the ETACS-ECU. Verify that the horn sounds
normally.
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. Verify that
the horn sounds normally.
STEP 11. Check horn connector A-36 (LOW) for loose,
corroded or damaged terminals, or terminals pushed back
in the connector.
Q: Is horn (LOW) connector A-36 in good condition?
YES : Go to Step 12.
NO : Repair or replace the damaged component(s). Refer
to GROUP 00E, Harness Connector Inspection
P.00E-2. Verify that the horn sounds normally.
STEP 12. Check the horn (LOW).
Connect the battery as shown, and verify that the horn sounds.
Q: Is the horn normal?
YES : Go to Step 13.
NO : Replace the horn (LOW). Verify that the horn sounds
normally.
Page 197 of 1500
SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-197
STEP 13. Check horn relay connector A-06X for loose,
corroded or damaged terminals, or terminals pushed back
in the connector.
Q: Is horn relay connector A-06X in good condition?
YES : Go to Step 14.
NO : Repair or replace the damaged component(s). Refer
to GROUP 00E, Harness Connector Inspection
P.00E-2. Verify that the horn sounds normally.
STEP 14. Check the wiring harness between horn relay
connector A-06X (terminal 4) and horn (LOW) connector
A-36 (terminal 1).
Q: Is the wiring harness between horn relay connector
A-06X (terminal 4) and horn (LOW) connector A-36
(terminal 1) in good condition?
YES : Replace the ETACS-ECU. Verify that the horn sounds
normally.
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. Verify that
the horn sounds normally.
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SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-199
STEP 17. Check the battery power supply circuit to the
horn relay. Measure the voltage at horn relay connector
A-06X.
(1) Disconnect horn relay connector A-06X and measure the
voltage available at the relay box side of the connector.
(2) Measure the voltage between terminal 1 and ground, and
also between terminal 2 and ground.
The voltage should measure approximately 12 volts
(battery positive voltage).
Q: Is the measured voltage approximately 12 volts (battery
positive voltage)?
YES : Go to Step 19.
NO : Go to Step 18.
STEP 18. Check the wiring harness between horn relay
connector A-06X (terminals 1 and 2) and the battery.
Q: Is the wiring harness between horn relay connector
A-06X (terminals 1 and 2) and the battery 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. Verify that
the horn sounds normally.
STEP 19. Check ETACS-ECU connector C-217 for loose,
corroded or damaged terminals, or terminals pushed back
in the connector.
Q: Is ETACS-ECU connector C-217 in good condition?
YES : Go to Step 20.
NO : Repair or replace the damaged component(s). Refer
to GROUP 00E, Harness Connector Inspection
P.00E-2. Verify that the horn sounds normally.
Page 200 of 1500
SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-200
STEP 20. Check the wiring harness between horn relay
connector A-06X (terminal 3) and ETACS-ECU connector
C-217 (terminal 44).
NOTE: Also check intermediate connector C-29 for loose, cor-
roded, or damaged terminals, or terminals pushed back in the
connector. If intermediate connector C-29 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 horn relay connector
A-06X (terminal 3) and ETACS-ECU connector C-217
(terminal 44) in good condition?
YES : Go to Step 21.
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. Verify that
the horn sounds normally.
Page 201 of 1500
SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-201
STEP 21. Check the wiring harness between horn relay
connector A-06X (terminal 4) and horn (HIGH) connector
A-37 (terminal 1).
Q: Is the wiring harness between horn relay connector
A-06X (terminal 4) and horn (HIGH) connector A-37
(terminal 1) in good condition?
YES : Replace the ETACS-ECU. Verify that the horn sounds
normally.
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. Verify that
the horn sounds normally.
Page 202 of 1500

SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-202
INSPECTION PROCEDURE E-3: Keyless Entry System: Encrypted code cannot be registered.
.
CIRCUIT OPERATION
The ETACS-ECU operates the encrypted code regis-
ter mode according to the following signals:
Key reminder switch
Hazard warning lamp switch
.
TECHNICAL DESCRIPTION (COMMENT)
If the encrypted code register mode cannot be set,
the input circuits from the switches described in
"CIRCUIT OPERATION" or the ETACS-ECU may be
defective.
If the encrypted code register mode can be set but
the transmitter cannot be registered, the transmitter
or the ETACS-ECU may be defective.
.
TROUBLESHOOTING HINTS
Refer to circuit diagrams GROUP-90
Refer to configuration diagrams GROUP-80
The key reminder switch may be defective
The hazard warning lamp switch may be defec-
tive
The transmitter may be defective
The ETACS-ECU may be defective
The wiring harness or connectors may have
loose, corroded, or damaged terminals, or termi-
nals pushed back in the connector
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
STEP 1. Verify trouble symptom.
Q: Can the encrypted code register mode be set?
YES : Go to Step 3.
NO : Go to Step 2.
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SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-203
STEP 2. Check the input signal (by using the pulse check
mode of the monitor).
Check the input signals from the following switches:
Key reminder switch
Hazard warning lamp switch
To prevent damage to diagnostic tool MB991958, always
turn the ignition switch to the "LOCK" (OFF) position
before connecting or disconnecting diagnostic tool
MB991958.
(1) Connect diagnostic tool MB991958.Refer to "How to
connect SWS monitor P.54B-13."
(2) 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."
(3) Check the switches (see table below) applicable for the
input signal check are operated.
(4) Check diagnostic tool MB991958 sounds or not.
Q: When the key reminder switch and the hazard warning
lamp switch are operated, does diagnostic tool
MB991958 sound in each case?
Buzzer of diagnostic tool MB991958 sounds normally. :
Replace the ETACS-ECU. Verify that the encrypted
code can be registered in the transmitter.
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."
diagnostic tool MB991958 does not sound when the
hazard warning lamp switch is turned from "OFF" to
"ON" : Refer to Inspection Procedure N-2 "ETACS-ECU
does not receive any signal from the hazard warning
lamp switch P.54B-436." ITEM NAME CHECK CONDITION
Key reminder switch Remove and reinsert the
ignition key
Hazard warning lamp switch Turn the hazard warning lamp
switch from "OFF" to "ON"
position.