Mitsubishi Evolution X. Manual - part 544

DIAGNOSIS

TSB Revision

KEYLESS OPERATION SYSTEM (KOS)

42B-83

(4) Check the wiring harness between outside transmitter 

antenna assembly (passenger's side) connector D-42 
(terminal No.1) and ground

OK: No continuity

Q: Is the wiring harness between outside transmitter 

antenna assembly (passenger's side) connector D-42 
(terminal Nos. 3, 2, 1) and the ground in good 
condition?
YES  : Go to Step 4.
NO [outside transmitter antenna assembly (passenger's 
side) connector D-42 terminal No.3 

− ground.] : Repair 

the wiring harness between outside transmitter 
antenna assembly (passenger's side) connector D-42 
(terminal No.3) and ground.

NO [outside transmitter antenna assembly (passenger's 
side) connector D-42 terminal No.2 

− ground.] : Repair 

the wiring harness between outside transmitter 
antenna assembly (passenger's side) connector D-42 
(terminal No.2) and the ground.

NO [outside transmitter antenna assembly (passenger's 
side) connector D-42 terminal No.1 

− ground.] : Repair 

the wiring harness between outside transmitter 
antenna assembly (passenger's side) connector D-42 
(terminal No.1) and the ground.

STEP 4. Keyless operation system communication test
Check that the communication with the outside transmitter 
antenna assembly (passenger's side) is normal (Refer to 
Antenna Test 

P.42B-275

).

Antennas to be checked

• Passenger side antenna (exterior)

OK: Normal is displayed.

Q: Is the check result normal?

YES : Go to Step 5.
NO :  Replace the outside transmitter antenna assembly 

(passenger's side).

STEP 5. Check whether the diagnostic trouble code is 
reset.
(1) Erase the DTC.
(2) Turn the ignition switch from the LOCK (OFF) position to the 

ON position.

(3) Check if the DTC is set.
Q: Is the DTC set?

YES : Replace KOS-ECU and register the ID codes (Refer 

to 

P.42B-12

).

NO :  The procedure is complete.

AC709707IH

Harness side: D-42

DIAGNOSIS

TSB Revision

KEYLESS OPERATION SYSTEM (KOS)

42B-84

DTC B240C: Tail gate antenna(outdoor) open

CAUTION

When replacing the ECU, always check that the 
communication circuit is normal.

AC609423

KOS-ECU

KEYLESS 
OPERATION 
KEY

OUTSIDE TRANSMISSION 
ANTENNA ASSEMBLY 
(TRUNK LID)

SKY  BLUE

SKY  BLUE

SKY  BLUE

SKY  BLUE

RED- BLA

CK

RED- BLA

CK

RED- BLA

CK

RED- BLA

CK

ORANGE

ORANGE

ORANGE

 Outside Transmission Antenna assembly (Trunk Lid) Circuit

AC

AC708950AW

C-42

Connectors: C-05, C-42

C-05

AC708951AZ

Connector: C-23

DIAGNOSIS

TSB Revision

KEYLESS OPERATION SYSTEM (KOS)

42B-85

.

DTC SET CONDITION

If an open circuit is detected in the outside transmit-
ter antenna (trunk lid), the DTC is set.

.

TECHNICAL DESCRIPTION (COMMENT)

When the ignition push switch is pressed, or when 
the antenna open circuit detection request is 
received from the diagnosis function, the failure is 
detected.

.

TROUBLESHOOTING HINTS

• Malfunction of the outside transmitter antenna 

assembly (trunk lid)

• Malfunction of the KOS-ECU

• Damaged wiring harness and connectors

DIAGNOSIS

STEP 1. Check KOS-ECU connector C-05 and outside 
transmitter antenna assembly (trunk lid) connector F-20 
for loose, corroded or damaged terminals, or terminals 
pushed back in the connector.
Q: Are KOS-ECU connector C-05 and outside transmitter 

antenna assembly (trunk lid) connector F-20 in good 
condition?
YES : Go to Step 2.
NO :  Repair or replace the damaged component(s). Refer 

to GROUP 00E, Harness Connector Inspection 

P.00E-2

. Check that the outside transmitter antenna 

assembly (trunk lid) works normally.

AC708955AL

Connector: D-17

D-17 (BR)

AC708970AK

Connector: F-20

F-20 (GR)

DIAGNOSIS

TSB Revision

KEYLESS OPERATION SYSTEM (KOS)

42B-86

STEP 2. Check the wiring harness between the KOS-ECU 
connector C-05 (terminal Nos. 6, 19, 40) and outside 
transmitter antenna assembly (trunk lid) connector F-20 
(terminal Nos. 1, 2, 3) for open circuit.
(1) Disconnect KOS-ECU connector C-05 and outside 

transmitter antenna assembly (trunk lid) connector F-20, 
and check the wiring harness.

(2) Check the wiring harness between KOS-ECU connector 

C-05 (terminal No.1) and outside transmitter antenna 
assembly (trunk lid) connector F-20 (terminal No.3).

OK: Continuity exists (2 

Ω or less)

(3) Check the wiring harness between KOS-ECU connector 

C-05 (terminal No.19) and outside transmitter antenna 
assembly (trunk lid) connector F-20 (terminal No.2).

OK: Continuity exists (2 

Ω or less)

AC709707FG

Harness side: C-05

Harness side: F-20

AC709707 FH

Harness side: C-05

Harness side: F-20