SWS DIAGNOSIS
SIMPLIFIED WIRING SYSTEM (SWS)54B-11
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. Ensure that the ignition switch is at the "LOCK" (OFF)
position.
2. Start up the personal computer.
3. Connect special tool MB991827 to special tool MB991824
and the personal computer.
4. Connect special tool MB991910 to special tool MB991824.
5. Connect special tool MB991910 to the data link connector.
6. Turn the power switch of special tool MB991824 to the "ON"
position.
NOTE: When special tool MB991824 is energized, special
tool MB991824 indicator lamp will be illuminated in a green
color.
7. Start the MUT-III system on the personal computer.
NOTE: Disconnecting diagnostic tool MB991958 is the reverse
of the connecting sequence, making sure that the ignition
switch is at the "LOCK" (OFF) position.
HOW TO READ AND ERASE DIAGNOSTIC
TROUBLE CODES
Required Special Tools:
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
To prevent damage to diagnostic tool MB991958, always
turn the ignition switch to the "LOCK" (OFF) position
before connecting or disconnecting diagnostic tool
MB991958.
NOTE: If the battery voltage is low, diagnostic trouble codes will
not be set. Check the battery if diagnostic tool MB991958 does
not display.
1. Connect diagnostic tool MB991958 to the data link
connector.
2. Turn the ignition switch to the "ON" position.
3. Select "Interactive Diagnosis" from the start-up screen.
4. Select "System select."
5. Choose "ETACS" .
6. Select "Diagnostic Trouble Code."
7. If a DTC is set, it is shown.
8. Choose "Erase DTCs" to erase the DTC.
SWS DIAGNOSIS
SIMPLIFIED WIRING SYSTEM (SWS)54B-12
HOW TO DIAGNOSE THE CAN BUS LINES
Required Special Tools:
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
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 to the data link
connector.
2. Turn the ignition switch to the "ON" position.
3. Select "CAN bus diagnosis" from the start-up screen.
4. When the vehicle information is displayed, confirm that it
matches the vehicle being diagnosed.
If they match, go to step 8.
If not, go to step 5.
5. Select the "view vehicle information" button.
6. Enter the vehicle information and select the "OK" button.
7. When the vehicle information is displayed, confirm again
that it matches the vehicle being diagnosed.
If they match, go to step 8.
If not, go to step 5.
8. Select the "OK" button.
9. When the optional equipment screen is displayed, choose
the one which the vehicle is fitted with, and then select the
"OK" button.
SWS DIAGNOSTIC TROUBLESHOOTING STRATEGYM1549000500906
1. Gather information about the problem from the
customer.
2. Verify that the condition described by the
customer exists.
NOTE: If an error occurs in the SWS communica-
tion line, the ECU isolated from the communica-
tion line performs a fail-safe or backup operation,
so the problem may not match the one shown in
the Trouble Symptom Chart. However, the cause
of the failure can be tracked down by performing
the following troubleshooting with the SWS moni-
tor.
3. Version number and destination check
Check whether the SWS version number and
destination meet the vehicle specifications. If they
are different, replace the ETACS-ECU with a
correct one.
4. Use diagnostic tool MB991958 (MUT-III Sub
Assembly) to select "ECU COMM Check" on the
SWS monitor display.Check whether the communication status of the
input- or output-signal-side ECU associated with
the defective function is normal.
If "OK" is displayed for all related ECUs, they
communicate with each other normally and the
input or output signal circuit system may be
defective. Therefore, check SWS monitor service
data.
If "NG" is displayed for any of the related ECUs,
something may be wrong with the ECU for which
"NG" appears, its power supply or grounding sys-
tem, or a wiring harness or connector between
the SWS monitor and the ECU. Check the wiring
harness and connectors associated with the ECU
and examine the ECU itself.
5. Service data on the SWS monitor
Select the defective function from the
function-specific diagnostic menu, and check the
service data that appears for each function item.
SWS DIAGNOSIS
SIMPLIFIED WIRING SYSTEM (SWS)54B-13
When the SWS communication line is monitored,
you can determine whether the problem lies in the
input or output signal circuit system by checking
whether communication data is correct:
If the switch condition does not meet the service
data display, the input signal is defective.
If the switch condition meets the service data dis-
play, the output signal system is defective.
Refer to circuit diagrams GROUP-90
Refer to configuration diagrams GROUP-80NOTE: In addition to the function-specific diag-
nostic menu, a service data menu is available for
SWS monitor service data to check all items for
each ECU.
6. Check the input signal circuit system
Check the relevant switch, sensor, input
signal-side ECU and their wiring harness and
connector.
7. Check the output signal circuit system
Check an output signal-side ECU, electrical load
components and their wiring harness and
connector.
HOW TO CONNECT SWS MONITORM1549014800706
Required Special Tools:
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: Probe Harness
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 the main harness A MB991910 before
connecting the SWS monitor harness (for column-ECU)
MB991812. Be sure to connect SWS monitor cartridge
MB991806 after turning on the V.C.I. MB991924.
1. Ensure that the ignition switch is at the "LOCK" (OFF)
position.
2. Start up the personal computer.
3. Connect special tool MB991827 to special tool MB991824
and the personal computer.
4. Connect special tool MB991910 to special tool MB991824.
5. Connect special tool MB991910 to the data link connector.
SWS DIAGNOSIS
SIMPLIFIED WIRING SYSTEM (SWS)54B-14
6. Remove the steering column cover.
7. Remove the steering column switch connector.
8. Connect special tool MB991812 to the column switch
connector.
9. Connect special tool MB991812 to special tool MB991806.
10.Connect special tool MB991806 to special tool MB991824.
11.Turn the power switch of special tool MB991824 to the "ON"
position.
NOTE: When special tool MB991824 is energised, special
tool MB991824 indicator lamp will be illuminated in a green
color.
12.Start the MUT-III system on the personal computer.
SWS DIAGNOSIS
SIMPLIFIED WIRING SYSTEM (SWS)54B-17
ETACS
NOTE: For item No.43, the diagnostic tool
MB991958 (MUT-III Sub Assembly) also displays
"ON" when the lamp reminder tone alarm or the seat
belt tone alarm function is triggered.
.
CHECK
ITEMITEM NO. DISPLAY ON
DIAGNOSTIC
TOOLCHECK CONDITION NORMAL
CONDITION
Tone alarm 43 BUZZER When requirements for sounding each
warning tone alarm are not satisfiedOFF
Front fog
lamps36 F.FOG LAMP
1. Lighting switch: HEAD
2. Fog lamp switch: ONON
Other than the condition above OFF
Driver’s door
switch32 FRONT DOOR
SWDriver’s door switch and Front passenger’s
door switch is on ON
Driver’s door switch and Front passenger’s
door switch is offOFF
Headlamp
automatic
shutoff
function35 H/L AUTO-CUT
1. Lighting switch: Other than OFF
2. Ignition switch: from ON or START to
LOCK (OFF) or ACC
3. Front door switch: ON (front door open) OFF to ON (after
approximately one
second)
When requirements for the headlamp
automatic shutoff are not satisfiedOFF
Ignition
switch (ACC)31 IG SW (ACC) Ignition switch: ACC or ON ON
Ignition switch: LOCK (OFF) or START OFF
Ignition
switch (IG1)30 IG SW (IG1) Ignition switch: ON or START ON
Ignition switch: LOCK (OFF) or ACC OFF
Windshield
intermittent
wiper interval37 INT WIPE
TIME1. Ignition switch: ACC or ON
2. Operate the intermittent wiper control,
and change the wiper intervalThe diagnostic tool
MB991958
(MUT-III Sub
Assembly)
displays
intermittent wiper
interval in
response to the
intermittent wiper
control positions.
SWS DIAGNOSIS
SIMPLIFIED WIRING SYSTEM (SWS)54B-18
Front-ECU, P/W, S/R
NOTE: For item No.70, the diagnostic tool
MB991958 (MUT-III Sub Assembly) also displays
"NG" under "ECU COMM Check" when it displays
"NO ACK" under the front-ECU check.NOTE: For item No.72, the diagnostic tool
MB991958 (MUT-III Sub Assembly) also displays
"NG" under "ECU COMM Check" when it displays
"NO ACK" under the sunroof-ECU check.
The table below shows the service data and their
normal condition, which are displayed during the
"Function Diag." The column "Normal condition"
shows values that are shown when each operation is
made.
.
CHECK
ITEMITEM NO. DISPLAY ON
DIAGNOSTIC
TOOLCHECK CONDITION NORMAL
CONDITION
Response by
the
front-ECU70 FRONT ECU
ACKLighting switch: Other than OFF (excluding
when high-beam is on) or the wiper switch
is at position other than OFF (ignition
switch: ACC or ON)NORMAL ACK
Ignition switch: Other than ON
Lighting switch: OFF
Wiper switch: OFFSLEEP ACK
Lighting switch: HEAD
Headlights: at high beamHI-BEAM ACK
Other than the condition above NO ACK
Response by
the
sunroof-ECU72 S/R ECU ACK
1. Door switch: OFF
2. Ignition switch: ON
OFF
3. While sunroof is offNORMAL ACK
SLEEP ACK (after
approximately 30
seconds)
1. Ignition switch: ON or START
2. One of the sunroof switches is onINPUT CHECK to
NORMAL ACK
Other than the above conditions NO ACK
SWS DIAGNOSIS
SIMPLIFIED WIRING SYSTEM (SWS)54B-23
For checking item "HEADLAMP HI", the diagnostic
tool MB991958 (MUT-III Sub Assembly) displays
"OFF" on the item No.2 "DIMMER SW" when the
headlamps are at high-beam. Therefore, the
diagnostic tool MB991958 (MUT-III Sub Assembly)
should display "ON" momentarily when the dimmer
switch is operated.
.
TURN SIGNAL
.
BUZZER
NOTE: The headlamp automatic shutoff function
operates approximately one second after the lighting
monitor tone alarm starts sounding, and then the
tone alarm ceases sounding.
.
ITEM ITEM NO. INPUT SIGNAL DISPLAY ON
DIAGNOSTIC TOOLNORMAL CONDITION
TURN-SIG.LH 10 Turn-signal lamp
switch (RH)T/S RH SW (COLUMN
ECU)OFF
11 Tu r n - s i g n a l l a m p
switch (LH)T/S LH SW (COLUMN
ECU)ON
30 Ignition switch
(IG1)IG SW (IG1) (ETACS ECU) ON
TURN-SIG.RH 10 Turn-signal lamp
switch (RH)T/S RH SW (COLUMN
ECU)ON
11 Tu r n - s i g n a l l a m p
switch (LH)T/S LH SW (COLUMN
ECU)OFF
30 Ignition switch
(IG1)IG SW (IG1) (ETACS ECU) ON
ITEM ITEM NO. INPUT SIGNAL DISPLAY ON DIAGNOSTIC
TOOLNORMAL CONDITION
LGT
MONI.ALRM00 Headlamp switch
HEADLAMP SW (COLUMN
ECU)Either is ON
01 Tail lamp switch TAILLAMP SW (COLUMN
ECU)
30 Ignition switch
(IG1)IG SW (IG1) (ETACS ECU) OFF
32 Front door switch FRONT DOOR SW (ETACS
ECU)ON
35 Headlamp
automatic shutoff
functionH/L AUTO-CUT (ETACS
ECU)OFF
43 Tone alarm BUZZER (ETACS ECU) ON
OTHER
ALARM30 Ignition switch
(IG1)IG SW (IG1) (ETACS ECU) ON
43 Tone alarm BUZZER (ETACS ECU) ON
SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-362
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 or START
Driver’s or front passenger’s door: open
(1) Operate diagnostic tool MB991958 according to the
procedure below to display "ETACS ECU."
a. Select "Interactive Diagnosis."
b. Select "System select."
c. Select "SWS."
d. Select "SWS MONITOR."
e. Select "Data List."
f. Select "ETACS ECU."
(2) Check that normal conditions are displayed for the items
described in the table below.
Q: Does the diagnostic tool MB991958 display the items
"IG SW (IG1)" and "FRONT DOOR SW" as normal
condition?
Normal conditions are displayed for all the items : Go to
St e p 3 .
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
(IG1) P.54B-408."
Normal condition is not displayed for "FRONT DOOR
SW" : Refer to Inspection Procedure M-4 "ETACS-ECU
does not receive any signal from the front door
switches P.54B-413." ITEM NO. ITEM NAME NORMAL CONDITION
ITEM 30 IG SW (IG1) ON
ITEM 32 FRONT DOOR SW ON