Mitsubishi Evolution X. Manual - part 529

DIAGNOSIS

TSB Revision

KEYLESS OPERATION SYSTEM (KOS)

42B-23

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

).

STEP 2. Using scan tool MB991958, read the engine 
control module diagnostic trouble code
Check again if the DTC is set to the engine control module.
Q: Is the DTC set?

YES : Troubleshoot the MFI system (Refer to GROUP 13A, 

Diagnostic trouble code chart 

P.13A-44

).

NO :  Go to Step 3.

STEP 3. Recheck for diagnostic trouble code.
Check again if the DTC is set to the KOS-ECU.
(1) Turn the ignition switch from "LOCK" (OFF) position to "ON" 

position.

(2) Check if DTC is set.
(3) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the DTC set?

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

to 

P.42B-12

). After registering the ID codes, go to 

Step 4.

NO :  The trouble can be an intermittent malfunction (Refer 

to GROUP 00 

− How to use 

Troubleshooting/inspection Service Points 

− How to 

Cope with Intermittent Malfunction 

P.00-15

.

AC608435

Data link connector

MB991827

MB991824

MB991910

AB

DIAGNOSIS

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KEYLESS OPERATION SYSTEM (KOS)

42B-24

STEP 4. Recheck for diagnostic trouble code.
Check again if the DTC is set to the KOS-ECU.
(1) Turn the ignition switch from "LOCK" (OFF) position to "ON" 

position.

(2) Check if DTC is set.
(3) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the DTC set?

YES : Replace the engine control module and record the 

VIN (Refer to GROUP 00 - How To Perform Vehicle 
Identification Number (VIN) Writing 

P.00-27

).

NO :  The procedure is complete.

DTC B1761: VIN code not programmed

CAUTION

• When the DTC No. B1761 is set, be sure to 

diagnose the CAN bus line.

• When replacing the ECU, always check that 

the communication circuit is normal.

.

DTC SET CONDITION

KOS-ECU sets DTC B1761 when no VIN is recorded 
in it.

.

TECHNICAL DESCRIPTION (COMMENT)

KOS-ECU determines that the abnormality is present 
when no VIN is recorded in it.

.

TROUBLESHOOTING HINTS

• VIN not programmed

• Malfunction of the 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

DIAGNOSIS

TSB Revision

KEYLESS OPERATION SYSTEM (KOS)

42B-25

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

).

STEP 2. Register the VIN and recheck the diagnostic 
trouble code.
Register VIN in KOS-ECU (Refer to GROUP 00 

− How to Per-

form Vehicle Identification Number (VIN) Writing 

P.00-27

) and 

recheck if the DTC is set.
(1) Turn the ignition switch from the "LOCK" (OFF) position to 

the "ON" position.

(2) Check if DTC is set.
(3) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the DTC set?

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

to 

P.42B-12

).

NO :  The procedure is complete.

AC608435

Data link connector

MB991827

MB991824

MB991910

AB

DIAGNOSIS

TSB Revision

KEYLESS OPERATION SYSTEM (KOS)

42B-26

DTC B1A08: Keyless/KOS key1 performance

 

DTC B1A09: Keyless/KOS key2 performance

 

DTC B1A0A: Keyless/KOS key3 performance

 

DTC B1A0B: Keyless/KOS key4 performance

CAUTION

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

.

DTC SET CONDITION

The mechanism which automatically changes a code 
for lock/unlock each time a lock operation is per-
formed is referred to as a rolling code. If KOS-ECU 
receives wrong signal (out of synchronization of a 
rolling code) from the keyless operation key, 
KOS-ECU memorizes DTC B1A08.

.

TECHNICAL DESCRIPTION (COMMENT)

• B1A08: If the difference between the rolling code 

for the keyless operation key 1 (the first keyless 
operation key registered with KOS-ECU) and that 
memorized by KOS-ECU is large, it is judged as 
abnormal.

• B1A09: If the difference between the rolling code 

for the keyless operation key 2 (the second key-
less operation key registered with KOS-ECU) and 
that memorized by KOS-ECU is large, it is judged 
as abnormal.

• B1A0A: If the difference between the rolling code 

for the keyless operation key 3 (the third keyless 
operation key registered with KOS-ECU) and that 
memorized by KOS-ECU is large, it is judged as 
abnormal.

• B1A0B: If the difference between the rolling code 

for the keyless operation key 4 (the fourth keyless 
operation key registered with KOS-ECU) and that 
memorized by KOS-ECU is large, it is judged as 
abnormal.

.

TROUBLESHOOTING HINTS

• Rolling code out of synchronization

• Malfunction of the keyless operation key

• Malfunction of the KOS-ECU

DIAGNOSIS

STEP 1. Synchronize the rolling code and 
recheck the diagnostic trouble code.
Synchronize the rolling codes, and check whether 
the DTC is reset.
(1) Erase the DTC.
(2) Turn the ignition switch from the LOCK (OFF) 

position to the ON position.

(3) Press the lock or unlock switch of the keyless 

operation key for which the diagnosis code is set 
at least once to synchronize the rolling codes.

(4) Check if the DTC is set.

Q: Is the DTC set?

YES : 

Go to Step 2.

NO : 

The diagnosis is complete.

STEP 2. Check whether the diagnostic trouble 
code is reset.
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-265

), and check 

whether the DTC 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 diagnosis is complete.