Mitsubishi Evolution X. Manual - part 538

DIAGNOSIS

TSB Revision

KEYLESS OPERATION SYSTEM (KOS)

42B-59

(5) Check the wiring harness between reciever anntena 

module connector C-08 (terminal No.12) and ground

OK: No continuity

Q: Is the wiring harness between receiver antenna module 

connector C-08 (terminal Nos.2, 1, 8, 12) and the ground 
in good condition?
YES  : Go to Step 10.
NO (receiver antenna module connector C-08 terminal 
No.2  

− ground.) : Repair the wiring harness between 

receiver antenna module connector C-08  (terminal 
No.2) and the ground.

NO (receiver antenna module connector C-08 terminal 
No.1 

− ground.) : Repair the wiring harness between 

receiver antenna module connector C-08  (terminal 
No.1) and the ground.

NO (receiver antenna module connector C-08 terminal 
No.8 

− ground.) : Repair the wiring harness between 

receiver antenna module connector C-08  (terminal 
No.8) and the ground.

NO (receiver antenna module connector C-08 terminal 
No.12 

− ground.) : Repair the wiring harness between 

receiver antenna module connector C-08  (terminal 
No.12) and the ground.

STEP 10. Replace the receiver antenna module, and check 
whether the diagnostic trouble code is reset.
(1) Turn the ignition switch from the "LOCK" (OFF) position to 

the "ON" position.

(2) 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.

AC709707HM

Harness side: C-08

DIAGNOSIS

TSB Revision

KEYLESS OPERATION SYSTEM (KOS)

42B-60

DTC B2401: Keyless/KOS key ID not registered

CAUTION

• If DTC B2401 is set, be sure to diagnose the 

CAN bus line.

• When replacing the ECU, always check that 

the communication circuit is normal.

.

DIAGNOSTIC FUNCTION

If no keyless operation key ID is registered with 
KOS-ECU or if the keyless operation key with ID not 
registered is used, KOS-ECU sets DTC B2401.

.

JUDGMENT CRITERIA

If the number of the registered keyless operation 
keys is 0, or the registration of a keyless operation 
key fails when the number of the registered keyless 
operation keys is 0, it is judged as abnormal.

.

PROBABLE CAUSES

• Malfunction of CAN bus line

• The registration of a keyless operation key ID 

fails when no keyless operation key ID is regis-
tered.

• Malfunction of the keyless operation key

• Malfunction of KOS-ECU

DIAGNOSIS

Required Special Tools:

• 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. Using scan tool MB991958, diagnose the CAN bus 
line.

CAUTION

To prevent damage to scan tool (MB991958), always turn 
the ignition switch to the "LOCK" (OFF) position before 
connecting or disconnecting scan tool (MB991958).
(1) Connect scan tool MB991958 to the data link connector.
(2) Turn the ignition switch to the "ON" position.
(3) Diagnose the CAN bus line.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the CAN bus line found to be normal?

YES : Go to Step 2.
NO :  Repair the CAN bus line (Refer to GROUP 54C, 

Diagnosis 

P.54C-14

).

AC608435

Data link connector

MB991827

MB991824

MB991910

AB

DIAGNOSIS

TSB Revision

KEYLESS OPERATION SYSTEM (KOS)

42B-61

STEP 2. Register the keyless operation key ID and recheck 
the diagnostic trouble code.
Register the keyless operation key ID (refer to 

P.42B-12

), and 

check whether the DTC is reset.
(1) Turn the ignition switch from the "LOCK" (OFF) position to 

the "ON" position.

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

YES : Go to Step 3.
NO :  The procedure is complete.

STEP 3. Replace the keyless operation key and recheck 
the diagnostic trouble code.
Replace the keyless operation key for which the DTC is set 
with a new one, register the key ID and keyless operation key 
ID (refer to 

P.42B-12

), and check whether the DTC is reset.

(1) Turn the ignition switch from the "LOCK" (OFF) position to 

the "ON" position.

(2) 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.

DIAGNOSIS

TSB Revision

KEYLESS OPERATION SYSTEM (KOS)

42B-62

DTC B2402: STL unit comm.(system ID)

 

DTC B2403: STL unit comm.(CRC)

 

DTC B2404: STL unit comm.(function code)

 

DTC B2405: STL unit comm.(rolling code)

 

DTC B2406: STL unit comm.(PTC operate)

 

DTC B2407: STL unit comm.(EEPROM)

 

DTC B2408: STL unit comm.(solenoid)

CAUTION

• If DTC B2402, B2403, B2404, B2405, B2406, 

B2407, or B2408 is set, diagnose the CAN bus 
lines.

• Whenever the steering lock unit is replaced, 

ensure that the communication circuit is nor-
mal.

.

KOS-ECU

KEY
REMINDER
SWITCH

Key Reminder Switch and KOS-ECU Circuit

AC708950AZ

Connector: C-05

AC708953AC

Connector: C-211