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SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-298
STEP 18. Check the wiring harness between headlamp
(LH) connector A-20 (terminals 3 and 4) and front-ECU
connector A-11X (terminal 10).
Q: Is the wiring harness between headlamp (LH) connector
A-20 (terminals 3 and 4) and front-ECU connector A-11X
(terminal 10) in good condition?
YES : Go to step 19.
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 headlamps illuminate normally.
STEP 19. Check the ground circuit to the front Headlamp
(LH). Measure the resistance at front combination lamp
(LH) connector A-20.
(1) Disconnect front combination lamp (LH) connector A-20
and measure the resistance available at the wiring harness
side of the connector.
(2) Measure the resistance value between terminals (5 and 1)
and ground.
The resistance should be 2 ohms or less.
Q: Is the measured resistance 2 ohms or less?
YES : .No action is necessary and testing is complete.
NO : Go to Step 20.
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SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-299
STEP 20. Check the wiring harness between headlamp
(LH) connector A-20 (terminals 5 and 1) and ground.
Q: Is the wiring harness between headlamp (LH) connector
A-20 (terminals 5 and 1) and ground 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 headlamps illuminate normally.
STEP 21. Check headlamp (RH) connector A-32 and
front-ECU connector A-11X for loose, corroded or
damaged terminals, or terminals pushed back in the
connector.
Q: Are headlamp (RH) connector A-32 and front-ECU
connector A-11X in good condition?
YES : Go to Step 22.
NO : Repair or replace the damaged component(s). Refer
to GROUP 00E, Harness Connector Inspection
P.00E-2. Verify that the headlamps illuminate
normally.
STEP 22. Check the headlamp (RH) bulb.
(1) Remove the headlamp (RH) bulb.
(2) Verify that the headlamp (RH) bulb is not damaged or
burned out.
Q: Is headlamp (RH) bulb normal?
YES : Go to Step 23.
NO : Replace the headlamp (RH) bulb. Verify that the
headlamps illuminate normally.
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SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-300
STEP 23 . Check the wiring harness between headlamp
(RH) connector A-32 (terminals 3 and 4) and front-ECU
connector A-11X (terminal 10).
Q: Is the wiring harness between headlamp (RH) connector
A-32 (terminals 3 and 4) and front-ECU connector A-11X
(terminal 10) in good condition?
YES : Go to step 24.
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 headlamps illuminate normally.
STEP 24. Check the ground circuit to the front Headlamp
(RH). Measure the resistance at front combination lamp
(RH) connector A-32.
(1) Disconnect front combination lamp (RH) connector A-32
and measure the resistance available at the wiring harness
side of the connector.
(2) Measure the resistance value between terminals (5 and 1)
and ground.
The resistance should be 2 ohms or less.
Q: Is the measured resistance 2 ohms or less?
YES : .No action is necessary and testing is complete.
NO : Go to Step 25.
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SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-301
STEP 25. Check the wiring harness between headlamp
(RH) connector A-32 (terminals 5 and 1) and ground.
Q: Is the wiring harness between headlamp (RH) connector
A-32 (terminals 5 and 1) and ground 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 headlamps illuminate normally.
INSPECTION PROCEDURE H-8: Headlamp and Taillamp: The High-beam indicator lamp does not
illuminate.
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
At the same time that the high beams are illumi-
nated, the ETACS-ECU sends a signal to illuminate
the high beam indicator via the CAN bus line.
.
TECHNICAL DESCRIPTION (COMMENT)
If the high beam indicator does not illuminate nor-
mally, connector(s), wiring harness in the CAN bus
lines, the ETACS-ECU or 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 combination meter may be defective
The ETACS-ECU may be defective
.
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SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-302
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 headlamps.
When the lighting switch is operated, check that the headlamps
illuminate/go off normally.
Q: Are the headlamps in good condition?
YES : Go to Step 2.
NO : First, repair the headlamps. Refer to Inspection
Procedure H-7 "One of the headlamps does not
illuminate P.54B-290."
STEP 2. Using Diagnostic Tool MB991958, diagnose the
CAN bus line.
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) Turn the ignition switch to the "ON" position.
(3) Diagnose the CAN bus line.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the CAN bus line found to be normal?
YES : Go to Step 3.
NO : Repair the CAN bus line (Refer to GROUP 54C,
Diagnosis P.54C-15).
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SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-305
INSPECTION PROCEDURE H-9: Headlamp and Taillamp: Headlamp automatic shutoff function does
not work 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 ETACS-ECU operates the headlamp automatic
shutdown function according to the following signals:
Ignition switch (IG1): OFF
Driver's door switch: ON
Taillamp switch: ON
Headlamp switch: ON
The ETACS-ECU operates the headlamp automatic
shutdown function under the following conditions:
Ignition key: Other than "ON" position
Driver's door: open
Taillamps or headlamps: on
.
TECHNICAL DESCRIPTION (COMMENT)
If the function does not work normally, the input cir-
cuit system from the switches, the ETACS-ECU or
the front-ECU may be defective (refer to "CIRCUIT
OPERATION").
.
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 front-ECU may be defective
Page 306 of 1500
SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-306
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 adjustment function.
Q: Has a setting other than "No auto-shutoff" been
selected for the headlamp automatic shutdown
function?
YES : Go to Step 2.
NO : Set the headlamp automatic shutdown function to
another setting other than "No auto-shutoff".
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SYMPTOM PROCEDURES
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STEP 2. Check the input signal by using "DATA LIST"
menu of the SWS monitor.
Check the input signals from the following switches:
Ignition switch: "ON" to "OFF"
Lighting switch: "TAIL" or "HEAD"
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 "LOCK" (OFF) position.
(3) Operate Diagnostic Tool MB991958 according to the
procedure below to display "H/L AUTO-CUT."
a. Select "Interactive Diagnosis."
b. Select "System select."
c. Select "SWS."
d. Select "SWS MONITOR."
e. Select "Function Diag."
f. Select "LIGHTING."
g. Select "H/L AUTO-CUT."
(4) Check that normal conditions are displayed for the items
described in the table below.
(5) When the driver's door is opened, check that normal
conditions are displayed for the items described in the table
below.
Q: Does the Diagnostic Tool MB991958 display the items
"TAILLAMP SW", "IG SW IG1", "FRONT DOOR SW" and
"H/L AUTO-CUT" as normal condition?
Normal conditions are displayed for all the items :
Replace the front-ECU. Verify that the headlamp
automatic shutdown function works normally.
Normal condition is not displayed for "TAILLAMP SW" :
Refer to Inspection Procedure M-5 "ETACS-ECU
does not receive any signal from the taillamp switch
P.54B-420."
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 ITEM NO. ITEM NAME NORMAL CONDITION
ITEM 01 TAILLAMP SW ON
ITEM 30 IG SW (IG1) OFF
ITEM NO. ITEM NAME NORMAL CONDITION
ITEM 32 FRONT DOOR SW ON
ITEM 35 H/L AUTO-CUT ON