Mitsubishi Montero (2002-2004). Manual — part 460

IGNITION SWITCH

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CHASSIS ELECTRICAL

54A-11

STEP 5. Check immobilizer-ECU connector D-121 and
ignition key ring antenna connector D-201 for loose,
corroded or damaged terminals, or terminals pushed back
in the connector.
Q: Are immobilizer-ECU connector D-121 and ignition key

ring antenna connector D-201 in good condition?
YES : Go to Step 6.
NO : Repair or replace them. Refer to GROUP 00E,

Harness Connector Inspection

P.00E-2

. Retest the

system.

STEP 6. Check the harness wires between immobilizer-
ECU connector D-121 and ignition key ring antenna
connector D-201.
Q: Are the harness wires between immobilizer-ECU

connector D-121 and ignition key ring antenna
connector D-201 in good condition?
YES : replace the immobilizer-ECU. Then register the

password (secret code) and encrypted code

P.54A-

22

. Retest the system.

NO : Repair them. Retest the system.

AC204170

CONNECTOR : D-121

CV

HARNESS SIDE

2

3

8 7

9

10

1
6

5

12

4

11

AC204172

CONNECTOR : D-201

AI

2

1

HARNESS SIDE

AC204170

CONNECTOR : D-121

CV

HARNESS SIDE

2

3

8 7

9

10

1
6

5

12

4

11

AC204172

CONNECTOR : D-201

AI

2

1

HARNESS SIDE

IGNITION SWITCH

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CHASSIS ELECTRICAL

54A-12

DTC12: Encrypted Codes are Not the Same or Not Registered

.

DTC SET CONDITION
The encrypted code sent by the transponder is not the same
encrypted code which is registered in the immobilizer-ECU.
NOTE: DTC 12 is always output together with MFI system DTC
P1610.

.

TROUBLESHOOTING HINTS

• The encrypted code in the ignition key has not been prop-

erly registered

• Malfunction of immobilizer-ECU

.

DIAGNOSIS
Was the encrypted code registered?

YES : Replace the immobilizer and then re-register the

encrypted code (Refer to

P.54A-22

.)

NO : Register the encrypted code (Refer to

P.54A-22

.)

SYMPTOM CHART

M1543007200793

SYMPTOMS

INSPECTION
PROCEDURE NO.

REFERENCE PAGE

Communication with scan tool MB991502 is impossible

1

P.54A-13

The ignition key cannot be registered

2

P.54A-19

Engine cranks but does not start

3

P.54A-20

IGNITION SWITCH

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CHASSIS ELECTRICAL

54A-13

SYMPTOM PROCEDURES

INSPECTION PROCEDURE 1: Communication with Scan Tool MB991502 is Impossible.

Immobilizer-ECU Power Supply, Ground and Powertrain Control Module

Communication Line Circuit

ACX01704AB

AC204745

CONNECTOR : B-22X

AC

AC204170

CONNECTORS : D-30, D-121

DO

D-30

D-121

IGNITION SWITCH

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CHASSIS ELECTRICAL

54A-14

.

CIRCUIT OPERATION
The Immobilizer-ECU is energized by the MFI relay
when the ignition switch is turned "ON". The PCM
transmits a signal from scan tool MB991502 to the
immobilizer-ECU as it is. In the same way, a signal
from the immobilizer-ECU is also transmitted to scan
tool MB991502 as it is.

.

TECHNICAL DESCRIPTION (COMMENT)

• This malfunction may be caused by a defective

immobilizer-ECU, PCM, or a defect in the com-
munication line between the immobilizer-ECU
and PCM. If this malfunction appears when the
MFI system and scan tool MB991502 can com-
municate each other, MFI system DTC P1610 will
reset.

• If the MFI system is normal, the MFI relay can be

determined as normal. In addition, if the MFI sys-
tem and scan tool MB991502 can communicate
each other, the circuits between the data link con-
nector and the PCM can determined as normal.
NOTE: If this malfunction appears, MFI system
DTC P1610 will be output.

.

TROUBLESHOOTING HINTS

• Malfunction of the immobilizer-ECU

• Malfunction of the PCM

• 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

• MB991502: Scan Tool (MUT-II)

STEP 1. Check if scan tool MB991502 can communicate
with the MFI system and if an MFI system DTC other than
P1610 is output.
Q: Can scan tool MB991502 communicate with the MFI

system? Is an MFI system DTC other than P1610
output?
YES : Go to Step 2.
NO : Refer to GROUP 13A, Multiport Fuel Injection

Diagnosis

P.13Ab-2

.

AC204171

CONNECTOR : D-116

AI

AC204176

CONNECTOR: E-111

AK