Mitsubishi L200. Manual — part 813

EXPLANATION ABOUT THE M.U.T.-III CAN BUS DIAGNOSTICS

CONTROLLER AREA NETWORK (CAN)

54C-11

ECU which
cannot
communicate
with the
M.U.T.-III

Possible
trouble spot

Logic for narrowing down trouble spot

ECU A

CAN bus line
(a) and power
supply system
to ECU A

ECU A communicates with the
M.U.T.-III via CAN bus lines (a)
and (b). The M.U.T.-III judges that
CAN bus line (b) is normal,
because it can communicate with
other ECUs. Possible trouble may
be present in CAN bus line (a) or
the power supply system to ECU
A.

AC204742 AZ

Diagnosis
connector

ECU B

ECU C

ECU D

ECU A

(a)

(b)

(c)

(d)

(e)

(f)

(g)

EXPLANATION ABOUT THE M.U.T.-III CAN BUS DIAGNOSTICS

CONTROLLER AREA NETWORK (CAN)

54C-12

2. If diagnosis code related to CAN communication

is set as past trouble, isolate opens as described
below.
NOTE: If you pinpoint trouble spot according to
diagnosis code, you should use time-out diagno-
sis code. diagnosis code related to failure infor-
mation is set when the data to be set contains an
error, so CAN bus line itself is probably normal.

NOTE: Time-out diagnosis code codes are stored
in each ECU memory individually. Therefore, it is
possible that these diagnosis code codes have
not been set simultaneously. If the trouble spot
cannot be found when you diagnose by judging
from multiple diagnosis code codes, check the
communication lines between each ECU.

ECU C

CAN bus line
(g) and power
supply system
to ECU C

ECU C communicates with the
M.U.T.-III via CAN bus lines (b),
(c), (d) and (g). The M.U.T.-III
judges that CAN bus lines (b), (c)
and (d) are normal, because it
can communicate with ECUs B
and D. Possible trouble may be
present in CAN bus line (g) or the
power supply system to ECU C.

AC204742 BA

ECU B

ECU C

ECU D

ECU A

(a)

(b)

(c)

(d)

(e)

(f)

(g)

Diagnosis
connector

ECU C and
ECU D

Trouble in
CAN bus line
(d)

ECUs C ad D communicate with
the M.U.T.-III via CAN bus lines
(b), (c), (d), (e) and (g). The
M.U.T.-III judges that CAN bus
lines (b) and (c) are normal,
because it can communicate with
ECU B. Possible trouble may be
present in CAN bus line (d), (e) or
(g) or the power supply system to
ECU D or C. CAN bus line (d) is
shared by ECUs C and D when
they communicate with the
M.U.T.-III, so CAN bus line (d) is
suspected as ultimate cause.
CAN bus line (g) or (e) and power
supply systems to ECU C or D
are also suspected as second
cause.

AC204742BB

ECU B

ECU C

ECU D

ECU A

(a)

(b)

(c)

(d)

(e)

(f)

(g)

Diagnosis
connector

ECU B and
ECU D

CAN bus line
(e) or (f) or
power supply
system to ECU
B or D

ECUs B ad D communicate with
the M.U.T.-III via CAN bus lines
(b), (c), (d), (e) and (f). The
M.U.T.-III judges that CAN bus
lines (b), (c) and (d) are normal,
because it can communicate with
ECU C. Possible trouble may be
present in CAN bus line (f) or (e)
or the power supply system to
ECU B or D.

AC204742 BC

ECU B

ECU C

ECU D

ECU A

(a)

(b)

(c)

(d)

(e)

(f)

(g)

Diagnosis
connector

ECU which
cannot
communicate
with the
M.U.T.-III

Possible
trouble spot

Logic for narrowing down trouble spot

Diagnosis
code to be set

Possible
trouble spot

Logic for narrowing down trouble spot

Time-out
diagnosis code
associated with
ECU D is stored
in ECU A, ECU
B and ECU C.

Trouble in
CAN bus line
(e) and power
supply system
to ECU D

When time-out diagnosis code
associated with ECU D is stored
in ECU A, B and C, or time-out
diagnosis code associated with
ECUs A, B and C is stored in
ECU D, or "bus off" diagnosis
code is stored in ECU D, CAN
bus line (e) is suspected. When
diagnosis code is not stored in
ECU D, the power supply to ECU
D is suspected.

AC204742 BD

ECU B

ECU C

ECU D

ECU A

(a)

(b)

(c)

(d)

(e)

(f)

(g)

Diagnosis
connector

Time-out
diagnosis code
associated with
ECUs A, B, C
and D is stored
in ECU.
"Bus off"
diagnosis code
is stored in ECU
D.
Time-out
diagnosis code
associated with
ECU A is stored
in ECUs B, C
and D.

Trouble in
CAN bus line
(a) or (c) and
power supply
system to ECU
A.

When time-out diagnosis code
associated with ECU A is stored
in ECUs B, C and D, or time-out
diagnosis code associated with
ECUs B, C and D is stored in
ECU A, or "bus off" diagnosis
code is stored in ECU A, CAN
bus line (a) or (c) is suspected.
When diagnosis code is not
stored in ECU A, the power
supply to ECU A is suspected.

AC204742 BF

ECU B

ECU C

ECU D

ECU A

(a)

(b)

(c)

(d)

(e)

(f)

(g)

Diagnosis
connector

Time-out
diagnosis code
associated with
ECUs B, C and
D is stored in
ECU A.
"Bus off"
diagnosis code
is stored in ECU
A.
Time-out
diagnosis code
codes
associated with
ECUs C and D
are stored in
ECU A and
ECU B.

Trouble in
CAN bus line
(d)

If time-out diagnosis code codes
associated with ECUs C and D
are stored in ECUs A and B, or
time-out codes associated with
ECUs A and B are stored in
ECUs C and D, CAN bus line (d)
is suspected. CAN bus line (g) or
(e) and power supply systems to
ECU C or D are also suspected
as second cause.

AC204742BQ

ECU B

ECU C

ECU D

ECU A

(a)

(b)

(c)

(d)

(e)

(f)

(g)

Diagnosis
connector

Time-out
diagnosis code
codes
associated with
ECUs A and B
are stored in
ECU C and
ECU D.

EXPLANATION ABOUT THE M.U.T.-III CAN BUS DIAGNOSTICS

CONTROLLER AREA NETWORK (CAN)

54C-13

TROUBLESHOOTING

CONTROLLER AREA NETWORK (CAN)

54C-14

TROUBLESHOOTING

CAN BUS DIAGNOSTICS TABLE

M1548300202222

This diagnosis applies only to the CAN bus lines. If a
different system is defective, proceed to the applica-
ble diagnosis section for each system. Observe the
diagnosis procedure below only when the CAN bus
line is defective.

CAUTION

During diagnosis, a diagnosis code associated with another system may be set when the ignition
switch is turned on with connector(s) disconnected. After completing the repair, confirm all systems
for diagnosis code(s). If diagnosis code(s) are set, erase them all.

M.U.T.-III screen

Diagnosis detail

Referenc
e page

(The ECUs that are not adopted are not displayed.)

Comment

ACA01245

: Red section on screen

AB

ETACS

DISPLAY

ABS/ASC

SAS

YR/G

A/C

AT

ENGINE

JC

JC

M.U.T.

Short circuit to
battery in red
displayed area is
estimated.

Diagnosis Item 1
Diagnose shorts in
the power supply
to CAN bus line

P.54C-20

Earthing in red
displayed area is
estimated.

Diagnosis Item 2
Diagnose shorts in
the earth to CAN
bus line

P.54C-42

Short circuit
between CAN_H
and CAN_L in
red displayed
area is
estimated.

Diagnosis Item 3
Diagnose shorts
between CAN_H
and L lines

P.54C-64

ACA01245

: Red section on screen

AC

ETACS

DISPLAY

ABS/ASC

SAS

YR/G

A/C

AT

ENGINE

JC

JC

M.U.T.

Disconnection in
red displayed
area is
estimated.

Diagnosis Item 4
Diagnose the
terminator
resistors

P.54C-81