Mitsubishi Evolution X. Manual - part 567

DIAGNOSIS

TSB Revision

KEYLESS OPERATION SYSTEM (KOS)

42B-175

.

TECHNICAL DESCRIPTION (COMMENT)

If only some keyless operation keys cannot be regis-
tered, the keyless operation key itself may be faulty. 
If no keyless operation key can be registered, the 
key assembly may have already been registered for 
another vehicle, or the KOS-ECU may be faulty.

.

TROUBLESHOOTING HINTS

• Malfunction of the keyless operation key

• Damaged wiring harness and connectors

• Malfunction of KOS-ECU

• Ignition key registered for other vehicle

DIAGNOSIS

Required Special Tools:

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

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

• MB991827 M.U.T.-III USB Cable

• MB991910 M.U.T.-III Main Harness A (Vehicles with 

CAN communication system)

STEP 1. Check the keyless operation key inserted in the 
key cylinder for interference.
Q: Are there other keyless operation 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 keyless 
operation key inserted in the key cylinder?
YES : Move away or remove other keyless operation 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 
keyless operation key. Then, go to step 2.

NO :  Go to Step 3.

STEP 2. Retest the system
Check that the keyless operation key can be registered.
Q: Is the keyless operation key that cannot be registered 

using scan tool?
YES : Go to Step 3.
NO :  The procedure is complete.

STEP 3. Check which keyless operation key cannot be 
registered.
Q: Can any one of the keyless operation keys be 

registered?
YES (Only some keys) : Replace the key that cannot be 

registered and register the ID codes (Refer to 

P.42B-265

). After registering the ID codes, go to Step 

5 .

NO (All keys) : Go to Step 4.

AC708955AM

Connector: D-14

DIAGNOSIS

TSB Revision

KEYLESS OPERATION SYSTEM (KOS)

42B-176

STEP 4. Retest the system
Check the scan tool screen when the key was not able to be 
registered.
Q: Is the error message of scan tool screen "Abnormality 

in key" ?
YES (Abnormality in key) : Carry out DTC B1A25: Key ID 

unmatched and DTC B1A35: Transponder read error 
(Refer to 

P.42B-29

 <B1A25>, 

P.42B-33

 <B1A35>). 

Then, go to Step 6. 

NO (ECU internal error) : Replace KOS-ECU and register 

the ID codes (Refer to 

P.42B-12

).

STEP 5. Retest the system
Check that the keyless operation key can be registered.
Q: Is the keyless operation key that cannot be registered 

using scan tool?
YES : Replace KOS-ECU and register the ID codes (Refer 

to 

P.42B-12

).

NO :  The procedure is complete.

STEP 6. Retest the system
Check that the keyless operation key can be registered.
Q: Is the keyless operation key that cannot be registered 

using scan tool?
YES : Go to Step 7.
NO :  The procedure is complete.

STEP 7. Check receiver antenna module connector C-08, 
receiver antenna assembly connector D-14, KOS-ECU 
connector C-05, joint connector (6) C-16 and intermittent 
connector C-41 for loose, corroded or damaged terminals, 
or terminals pushed back in the connector.
Q: Is the receiver antenna module connector C-08, receiver 

antenna assembly connector D-14, KOS-ECU connector 
C-05, joint connector (6) C-16 and intermittent 
connector C-41 in good condition?
YES : Go to Step 8.
NO :  Repair the defective connector.

DIAGNOSIS

TSB Revision

KEYLESS OPERATION SYSTEM (KOS)

42B-177

STEP 8. Check the wiring harness between the receiver 
antenna assembly connector D-14 (terminal Nos.1, 8, 12, 3, 
5) and the KOS-ECU connector C-05 (terminal Nos.12, 32, 
7, 9, 13) for open circuit.
(1) Disconnect reciever anntena assembly connector D-14 and 

KOS-ECU connector C-05, and check the wiring harness.

(2) Check the wiring harness between reciever anntena 

assembly connector D-14 (terminal No.1) and KOS-ECU 
connector C-05 (terminal No.12)

OK: Continuity exists (2 

Ω or less)

(3) Check the wiring harness between reciever anntena 

assembly connector D-14 (terminal No.8) and KOS-ECU 
connector C-05 (terminal No.32)

OK: Continuity exists (2 

Ω or less)

(4) Check the wiring harness between reciever anntena 

assembly connector D-14 (terminal No.12) and KOS-ECU 
connector C-05 (terminal No.7)

OK: Continuity exists (2 

Ω or less)

(5) Check the wiring harness between reciever anntena 

assembly connector D-14 (terminal No.3) and KOS-ECU 
connector C-05 (terminal No.9)

OK: Continuity exists (2 

Ω or less)

AC709707

AC709707

Harness side: C-05

DK

Harness side: D-14

AC709707

Harness side: C-05

DL

Harness side: D-14

AC709707DM

Harness side: D-14

Harness side: C-05

AC709707DN

Harness side: C-05

Harness side: D-14

DIAGNOSIS

TSB Revision

KEYLESS OPERATION SYSTEM (KOS)

42B-178

(6) Check the wiring harness between reciever anntena 

assembly connector D-14 (terminal No.5) and KOS-ECU 
connector C-05 (terminal No.13)

OK: Continuity exists (2 

Ω or less)

Q: Is the wiring harness between receiver antenna 

assembly connector D-14 (terminal Nos.1, 8, 12, 3, 5) 
and the KOS-ECU connector C-05 (terminal Nos.12, 32, 
7, 9, 13) in good condition?
YES  : Go to Step 9.
NO (receiver antenna assembly connector D-14 terminal 
No.1  

− KOS-ECU connector C-05 terminal No.12.) : 

Repair the wiring harness between receiver antenna 
assembly connector D-14  (terminal No.1) and the 
KOS-ECU connector C-05 (terminal No.12).

NO (receiver antenna assembly connector D-14 terminal 
No.8 

− KOS-ECU connector C-05 terminal No.32.) : 

Repair the wiring harness between receiver antenna 
assembly connector D-14  (terminal No.8) and the 
KOS-ECU connector C-05 (terminal No.32).

NO (receiver antenna assembly connector D-14 terminal 
No.12 

− KOS-ECU connector C-05 terminal No.7.) : 

Repair the wiring harness between receiver antenna 
assembly connector D-14  (terminal No.12) and the 
KOS-ECU connector C-05 (terminal No.7).

NO (receiver antenna assembly connector D-14 terminal 
No.3 

− KOS-ECU connector C-05 terminal No.9.) : Repair 

the wiring harness between receiver antenna 
assembly connector D-14  (terminal No.3) and the 
KOS-ECU connector C-05 (terminal No.9).

NO (receiver antenna assembly connector D-14 terminal 
No.5 

− KOS-ECU connector C-05 terminal No.13.) : 

Repair the wiring harness between receiver antenna 
assembly connector D-14  (terminal No.5) and the 
KOS-ECU connector C-05 (terminal No.13).

AC709707DO

Harness side: C-05

Harness side: D-14