Mitsubishi Evolution X. Manual - part 585

DIAGNOSIS

TSB Revision

KEYLESS OPERATION SYSTEM (KOS)

42B-247

STEP 7. Using scan tool MB991958, read the diagnostic 
trouble code.

CAUTION

To prevent damage to scan tool MB991958, always turn the 
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991958.
(1) Connect scan tool MB991958. Refer to "How to connect 

scan tool (M.U.T.-III) 

P.42B-10

."

(2) Turn the ignition switch to the "ON" position.
(3) Check whether the KOS-ECU related DTC is set.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the DTC set?

YES : Diagnose the KOS-ECU. Refer to 

P.42B-20

.

NO :  Go to Step 8.

STEP 8. Check of the troubles
Check if the keyless entry answerback function works normally.
Q: Is the check result normal?

YES : The diagnosis is complete.
NO :  Replace ETACS-ECU.

AC608435

Data link connector

MB991827

MB991824

MB991910

AB

DIAGNOSIS

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KEYLESS OPERATION SYSTEM (KOS)

42B-248

Inspection Procedure 17: The Trunk is not opened when the keyless operation key "TRUNK" button is 
operated.

CAUTION

Before replacing the ECU, ensure that the power 
supply circuit, the ground circuit and the com-
munication circuit are normal.

AC708974

ETACS-ECU

BLA

CK

BLA

CK

GREEN

BLA

CK

-BLUE

YELLO

W

-GREEN

WHITE

-BLUE

KEYLESS OPERATION KEY
"TRUNK"BUTTON

INPUT SIGNAL

INTERFACE

CIRCUIT

CAN DRIVE

CIRCUIT

JOINT

CONNECTOR 

(CAN1)

Keyless Operation Key "TRUNK" Input Signal

AC

JOINT 
CONNECTOR 
(6)

RECEIVER

RECEIVER 
ANTENNA 
ASSEMBLY

RED

RED

GREEN -RED

GREEN -RED

YELLOW

-GREEN

YELLOW

-GRAY

YELLOW

-GRAY

BROWN -WHITE

BROWN -WHITE

RED- WHITE

RED- WHITE

RED- WHITE

RED- BLA

CK

RED- WHITE

RED

GREEN -RED

BROWN -WHITE

RED- WHITE

TRUNK 

LID OPEN 

RELAY

TRUNK LID 

LATCH

KOS-ECU

DIAGNOSIS

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KEYLESS OPERATION SYSTEM (KOS)

42B-249

.

TECHNICAL DESCRIPTION (COMMENT)

The receiver antenna assembly receives the trunk 
signals from the keyless operation key, and sends 
them to KOS-ECU, and further to ETACS-ECU. Then 
the ETACS-ECU determines to actuate the trunk 
open function of the keyless entry system.

.

TROUBLESHOOTING HINTS

• The keyless operation key may be defective

• The receiver antenna assembly may be defective

• The KOS-ECU may be defective

• The ETACS-ECU may be defective

• The wiring harness or connectors may have 

loose, corroded, or damaged terminals, or termi-
nals pushed back in the connector

DIAGNOSIS

Required Special Tools:

• MB992006: Extra fine probe

• MB991223: Harness set

• MB991958 Scan Tool (M.U.T.-III Sub Assembly)

• MB991824: Vehicles Communication Interface (V.C.I.)

• MB991827 M.U.T.-III USB Cable

• MB991910 M.U.T.-III Main Harness A

STEP 1. Check the operation of the keyless operation 
system (keyless entry system).
Operate the keyless operation key and check that all doors lock 
and unlock.
Q: Is the check result normal?

YES : Go to Step 2.
NO :  Refer to inspection procedure 14: "Keyless entry 

system does not work 

P.42B-234

."

AC708972AC

Connector: C-311

ETACS-ECU

AC708955AL

Connector: D-17

D-17 (BR)

AC708970AD

Connectors: F-19, F-27

F-27

F-19

DIAGNOSIS

TSB Revision

KEYLESS OPERATION SYSTEM (KOS)

42B-250

STEP 2. Using scan tool MB991958, read the diagnostic 
trouble code.

CAUTION

To prevent damage to scan tool MB991958, always turn the 
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991958.
(1) Connect scan tool MB991958. Refer to "How to connect 

scan tool (M.U.T.-III) 

P.42B-10

."

(2) Turn the ignition switch to the "ON" position.
(3) Check whether the KOS-ECU related DTC is set.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the DTC set?

YES : Diagnose the KOS-ECU. Refer to 

P.42B-20

.

NO :  Go to Step 3.

AC608435

Data link connector

MB991827

MB991824

MB991910

AB