Mitsubishi L200. Manual - part 667

IMMOBILIZER SYSTEM

CHASSIS ELECTRICAL

54A-35

STEP 4. Check whether the diagnosis code is 
reset.
(1) Turn the ignition switch to the "LOCK" (OFF) 

position once, and then turn it to the ON position 
again.

(2) Check if diagnosis code No.B1722 is set as a 

current trouble.

Q: Is diagnosis code No.B1722 set as a current 

trouble?
YES : 

Replace the key reminder switch (ignition 

key ring antenna), and then go to Step 5.

NO : 

If diagnosis code No.B1722 is set as a past 
trouble, erase the diagnosis code that is set 
as a past trouble, and the diagnosis is 
complete.

STEP 5. Check whether the diagnosis code is 
reset.
(1) Turn the ignition switch to the "LOCK" (OFF) 

position once, and then turn it to the ON position 
again.

(2) Check if diagnosis code No.B1722 is set as a 

current trouble.

Q: Is diagnosis code No.B1722 set as a current 

trouble?
YES : 

Replace the ETACS-ECU and register the 

ID codes (Refer to 

P.54A-39

). After 

registering the ID codes, return to Step 1.

NO : 

If diagnosis code No.B1722 is set as a past 
trouble, erase the diagnosis code that is set 
as a past trouble, and the diagnosis is 
complete.

Code No. B1731: Communication error with the engine-ECU

CAUTION

If diagnosis code No.B1731 is set in the immobi-
lizer-ECU, diagnose the CAN bus lines.

CAUTION

Whenever the ECU is replaced, ensure that the 
input and output signal circuits are normal.
TROUBLE JUDGMENT
If the immobilizer-ECU cannot receive any signals 
from the engine-ECU, diagnosis code B1731 will be 
set.

COMMENT ON TROUBLE SYMPTOM
Connector(s) or wiring harness in the CAN bus lines 
between the immobilizer-ECU and the engine-ECU, 
the power supply system to the engine-ECU, the 
engine-ECU itself, or the immobilizer-ECU itself may 
be defective.
NOTE: Diagnosis code No.B1731 is always set 
along with MPI system diagnosis code No.U1117.

PROBABLE CAUSES

• Malfunction of engine-ECU

• Malfunction of immobilizer-ECU

• Damaged harness wires and connectors

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III CAN bus diagnostics.
Use the M.U.T.-III to diagnose the CAN bus lines.

Q: Is the check result normal?

YES : 

Go to Step 2.

NO : 

Repair the CAN bus line (Refer to GROUP 
54C 

− Troubleshooting ). Repair the CAN 

bus line and go to Step 3.

STEP 2. Check whether the diagnosis code is 
reset.
Check again if the diagnosis code is set.
(1) Turn the ignition switch to the "LOCK" (OFF) 

position once, and then turn it to the ON position 
again.

(2) Check that diagnosis code No.B1731 is not set 

as a current trouble.

Q: Is diagnosis code No.B1731 set?

YES : 

Replace the immobilizer-ECU and register 

the ID codes. (Refer to 

P.54A-39

.) After 

registering the ID codes, go to Step 3.

NO : 

The diagnosis is complete. If another 
diagnosis code is set, refer to Diagnosis 
Code Chart 

P.54A-30

.

STEP 3. Check whether the diagnosis code is 
reset.
Recheck if the diagnosis code is set.
(1) Turn the ignition switch to the "LOCK" (OFF) 

position once, and then turn it to the ON position 
again.

(2) Check that diagnosis code No.B1731 is not set 

as a current trouble.

Q: Is diagnosis code No.B1731 set?

IMMOBILIZER SYSTEM

CHASSIS ELECTRICAL

54A-36

YES : 

Replace the engine-ECU and resister the ID 

code. (Refer to 

P.54A-39

.) 

NO : 

The diagnosis is complete. If another 
diagnosis code is set, refer to Diagnosis 
Code Chart 

P.54A-30

.

Code No.B1761: Chassis No. not recorded

CAUTION

Whenever the ECU is replaced, ensure that the 
input and output signal circuits are normal.
TROUBLE JUDGMENT
If the chassis No. data is not written when the 
ETACS-ECU is replaced, the ETACS-ECU sets diag-
nosis code No.B1761.

PROBABLE CAUSES

• Chassis No. not written

• Damaged harness wires and connectors

• Malfunction of ETACS-ECU

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III CAN bus diagnostics.
Use the M.U.T.-III to diagnose the CAN bus lines.

Q: Is the check result normal?

YES : 

Go to Step 2.

NO : 

Repair the CAN bus line (Refer to GROUP 
54C 

− Troubleshooting ). Repair the CAN 

bus line.

STEP 2. Write the Chassis No. 
Write the chassis No. data to the ETACS-ECU  
[Refer to GROUP 00 

− How to perform chassis 

number (Chassis No.) writing ].

Q: Is diagnosis code No.B1761 set?

YES : 

Replace the ETACS-ECU and register the 

ID codes (Refer to 

P.54A-39

).

NO : 

The procedure is complete.

Code No.B1766: Transponder registered for other vehicle

CAUTION

Whenever the ECU is replaced, ensure that the 
input and output signal circuits are normal.
TROUBLE JUDGMENT
If the key registered for another vehicle is used to 
start the engine, the ETACS-ECU sets diagnosis 
code No.B1766.

PROBABLE CAUSES

• Ignition key (key ID) is another vehicle's key

• Ignition key (key ID) is new key

• Malfunction of ETACS-ECU

DIAGNOSIS PROCEDURE

STEP 1. All ignition keys registration
Check that the all ignition keys are registered.

Q: Is the check result normal?

YES : 

Go to Step 2

NO : 

Register the all ignition keys. Refer to 

P.54A-39

.

STEP 2. M.U.T.-III CAN bus diagnostics.
Use the M.U.T.-III to diagnose the CAN bus lines.

Q: Is the check result normal?

YES : 

Go to Step 3

NO : 

Repair the CAN bus line (Refer to GROUP 
54C 

− Troubleshooting ). Repair the CAN 

bus line.

STEP 3. Check with another key that has already 
been registered.
Turn the ignition switch to the ON position using 
another key that has already been registered.

Q: Is the diagnosis code set?

IMMOBILIZER SYSTEM

CHASSIS ELECTRICAL

54A-37

YES : 

Replace the all ignition keys or by the 

service key set, and register the ID codes 
(Refer to 

P.54A-39

).  After registering the ID 

codes, go to Step 4.

NO : 

Replace the ignition key that the diagnosis 
code is set, and register the ID codes again 
(Refer to 

P.54A-39

). After registering the ID 

codes, go to Step 4.

STEP 4. Check whether the diagnosis code is 
reset.
Check again if the diagnosis code is set.
(1) Turn the ignition switch to the "LOCK" (OFF) 

position once, and then turn it to the ON position 
again.

(2) Check that diagnosis code No.B1766 is not set.

Q: Is diagnosis code No.B1766 set?

YES : 

Replace the ETACS-ECU and register the 

ID codes (Refer to 

P.54A-39

).

NO : 

The procedure is complete.

TROUBLE SYMPTOM CHART

M1541100300176

CAUTION

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

SYMPTOM PROCEDURES

Inspection Procedure 1: The ignition key cannot be registered with the M.U.T.-III.

COMMENTS ON TROUBLE SYMPTOM
If only some ignition keys cannot be registered, the 
ignition key itself may be defective. If no ignition key 
can be registered, the key assembly may have 
already been registered for another vehicle, or the 
ETACS-ECU may be defective.

PROBABLE CAUSES

• Malfunction of ignition key

• Damaged harness wires and connectors

• Malfunction of ETACS-ECU

• Malfunction of engine-ECU

• Transponder registered for other vehicle

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III CAN bus diagnostics.
Use the M.U.T.-III to diagnose the CAN bus lines.

Q: Is the check result normal?

YES : 

Go to Step 2.

NO : 

Repair the CAN bus line (Refer to GROUP 
54C 

− Troubleshooting ). Repair the CAN 

bus line.

STEP 2. Check the ignition key inserted in the 
key cylinder for interference.

Q: Are there other ignition keys or anything that 

interferes with the communication (things that 
generate radio waves such as magnets and an air-
cleaning device that has a power plug) near the 
ignition key inserted in the key cylinder?
YES : 

Move away or remove other ignition keys or 

things that interfere with the communication 
(things that generate radio waves such as 
magnets and a air-cleaning device that has 
a power plug) near the ignition key. Then, 
go to step 3.

NO : 

Go to Step 4.

Trouble symptom

Inspection 
procedure No.

Reference 
page

The ignition key cannot be registered with the M.U.T.-III.

1

P.54A-37

The engine does not start (Cranking occurs but initial combustion does not). 2

P.54A-38

IMMOBILIZER SYSTEM

CHASSIS ELECTRICAL

54A-38

STEP 3. Retest the system.
Check that the ignition key can be registered.

Q: Is the check result normal?

YES : 

The procedure is complete.

NO : 

Go to Step 4.

STEP 4. Check which ignition key cannot be 
registered.

Q: Are there only some ignition keys that cannot be 

registered?
Only some keys : 

Replace the key that cannot be 

registered and register the ID codes (Refer 
to 

P.54A-39

). After registering the ID codes, 

go to Step 6.

All keys : 

Go to Step 5.

STEP 5. Retest the system.
Check the M.U.T.-III screen when the key was not 
able to be registered.

Q: Which error message did the M.U.T.-III display?

Defective key : 

Carry out the troubleshooting for 

diagnosis code B1722 Transponder 
Antenna Failure (Refer to 

P.54A-32

). Then, 

go to Step 6.

ECU internal error : 

Replace the ETACS-ECU and 

register the ID codes (Refer to 

P.54A-39

). 

After registering the ID codes, go to Step 6.

STEP 6. Retest the system.
Check that the ignition key can be registered.

Q: Is the check result normal?

YES : 

The procedure is complete.

NO : 

Replace the ETACS-ECU and register the 
ID codes (Refer to 

P.54A-39

).

Inspection Procedure 2: The engine does not start (cranking occurs but initial combustion does not).

COMMENTS ON TROUBLE SYMPTOM
If the fuel injection does not work, the ETACS- ECU 
and the diesel system may be defective. It is no prob-
lem with the malfunction above when the engine is 
started with unregistered ignition key.

PROBABLE CAUSES

• Malfunction of diesel system

• Malfunction of ETACS-ECU

• Damaged harness wires and connectors

• Malfunction of ignition key

• Chassis No. not written

DIAGNOSIS PROCEDURE

STEP 1. Battery voltage check
Measure the battery voltage when cranking.

OK: 8 V or more

Q: Is the check result normal?

YES : 

Go to Step 2.

NO : 

Check the battery (Refer to 

P.54A-9

).

STEP 2. M.U.T.-III CAN bus diagnostics
Use the M.U.T.-III to diagnose the CAN bus lines.

Q: Is the check result normal?

YES : 

Go to Step 3.

NO : 

Repair the CAN bus line (Refer to GROUP 
54C 

− Troubleshooting ).

STEP 3. M.U.T.-III other system diagnosis code
Check whether the diesel system-related diagnosis 
code is set.

Q: Is the diagnosis code set?

YES : 

Refer to GROUP 13A, Troubleshooting .

NO : 

Go to Step 4.

STEP 4. M.U.T.-III diagnosis code
Check whether the engine immobilizer system-
related diagnosis code is set.

Q: Is the diagnosis code set?

YES : 

Refer to 

P.54A-30

.

NO : 

Go to Step 5.

STEP 5. Check that the engine starts. 

Q: Does the engine start?

YES : 

The procedure is complete.

NO : 

Refer to GROUP 13A, Troubleshooting . 
Replace the ETACS-ECU and register the 
ID codes when the cause of the failure 
cannot be tracked down by performing the 
troubleshooting in GROUP 54A (Refer to 

P.54A-39

).