Mitsubishi Outlander (2013+). Manual - part 540

TROUBLESHOOTING <KOS-ECU>

KEYLESS OPERATION SYSTEM (KOS)

42B-21

YES : 

Replace KOS-ECU and register the ID 

codes (Refer to 

P.42B-88

).

NO : 

The diagnosis is complete.

Code No.B2401 Keyless/KOS key ID not registered

CAUTION

• If the diagnosis code No. B2401 is set, be sure 

to diagnose the CAN bus line.

• When replacing the ECU, always check that 

the communication circuit is normal.

DIAGNOSIS FUNCTION

If no keyless operation key ID is registered with 
KOS-ECU, KOS-ECU sets the diagnosis code No. 
B2401.

JUDGMENT CRITERIA

If the number of the registered keyless operation 
keys or spare key 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

• 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 PROCEDURE

1. Register the keyless operation key ID and 

recheck the diagnosis code.

2. Replace the keyless operation key and recheck 

the diagnosis code.

Code No.B240A DR side antenna(outdoor) open

CAUTION

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

DIAGNOSTIC FUNCTION

If an open circuit is detected in the outside transmis-
sion antenna assembly (driver's side), the diagnosis 
code is set.

JUDGMENT CRITERIA

While the engine switch is turned to the OFF posi-
tion, the system has detected an open circuit in the 
antenna.

PROBABLE CAUSES

• Malfunction of the outside transmission antenna 

assembly (driver's side)

• Malfunction of the KOS-ECU

• Damaged wiring harness and connectors

DIAGNOSIS PROCEDURE

STEP 1. Check of short to power supply, short to 
earth, and open circuit in EDRP, EDRG line 
between the outside transmission antenna 
assembly (driver's side) connector and the 
KOS-ECU connector.

Q: Is the check result normal?

YES : 

Go to Step 2

NO : 

Repair the connectors or wiring harness.

STEP 2. Keyless operation system 
communication test
Check that the communication with the outside trans-
mission antenna assembly (driver's side) is normal 
(Refer to Antenna Test 

P.42B-89

).

Antennas to be checked

• Front antenna (outdoor)

OK: Normal is displayed.

Q: Is the check result normal?

YES : 

Go to Step 3

NO : 

Replace the outside transmission antenna 
assembly (driver's side).

TROUBLESHOOTING <KOS-ECU>

KEYLESS OPERATION SYSTEM (KOS)

42B-22

STEP 3. Check whether the diagnosis code is 
reset.
(1) Erase the diagnosis code.
(2) Turn the power supply mode of the engine switch 

from OFF to ON.

(3) Check if the diagnosis code is set.
(4) Turn the power supply mode of the engine switch 

from OFF to ON.

Q: Is the diagnosis code set?

YES : 

Replace KOS-ECU and register the ID 

codes (Refer to 

P.42B-88

).

NO : 

Intermittent malfunction is suspected (Refer 
to GROUP 00 

− How to Use 

Troubleshooting/Inspection Service Points 

− 

How to Deal with Intermittent Malfunction ).

Code No.B240B PS side antenna(outdoor) open 

CAUTION

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

DIAGNOSTIC FUNCTION

If an open circuit is detected in the outside transmis-
sion antenna assembly (passenger's side), the diag-
nosis code is set.

JUDGMENT CRITERIA

While the engine switch is turned to the OFF posi-
tion, the system has detected an open circuit in the 
antenna.

PROBABLE CAUSES

• Malfunction of the outside transmission antenna 

assembly (passenger's side)

• Malfunction of the KOS-ECU

• Damaged wiring harness and connectors

DIAGNOSIS PROCEDURE

STEP 1. Check of short to power supply, short to 
earth, and open circuit in EASP, EASG line 
between the outside transmission antenna 
assembly (passenger's side) connector and the 
KOS-ECU connector.

Q: Is the check result normal?

YES : 

Go to Step 2

NO : 

Repair the connectors or wiring harness.

STEP 2. Keyless operation system 
communication test
Check that the communication with the outside trans-
mission antenna assembly (passenger's side) is nor-
mal (Refer to Antenna Test 

P.42B-89

).

Antennas to be checked

• Front side antenna (outdoor)

OK: Normal is displayed.

Q: Is the check result normal?

YES : 

Go to Step 3

NO : 

Replace the outside transmission antenna 
assembly (passenger's side).

STEP 3. Check whether the diagnosis code is 
reset.
(1) Erase the diagnosis code.
(2) Turn the power supply mode of the engine switch 

from OFF to ON.

(3) Check if the diagnosis code is set.
(4) Turn the power supply mode of the engine switch 

from OFF to ON.

Q: Is the diagnosis code set?

YES : 

Replace KOS-ECU and register the ID 

codes (Refer to 

P.42B-88

).

NO : 

Intermittent malfunction is suspected (Refer 
to GROUP 00 

− How to Use 

Troubleshooting/Inspection Service Points 

− 

How to Deal with Intermittent Malfunction ).

Code No.B240C Tail gate antenna(outdoor) open

CAUTION

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

DIAGNOSTIC FUNCTION

If an open circuit is detected in the outside transmis-

sion antenna assembly (tailgate), the diagnosis code 
is set.

TROUBLESHOOTING <KOS-ECU>

KEYLESS OPERATION SYSTEM (KOS)

42B-23

JUDGMENT CRITERIA

While the engine switch is turned to the OFF posi-
tion, the system has detected an open circuit in the 
antenna.

PROBABLE CAUSES

• Malfunction of the outside transmission antenna 

assembly (tailgate)

• Malfunction of the KOS-ECU

• Damaged wiring harness and connectors

DIAGNOSTIC PROCEDURE

STEP 1. Check of short to power supply, short to 
earth, and open circuit in EGTP, EGTG line 
between the outside transmission antenna 
assembly (tailgate) connector and the KOS-ECU 
connector.

Q: Is the check result normal?

YES : 

Go to Step 2

NO : 

Repair the connectors or wiring harness.

STEP 2. Keyless operation system 
communication test
Check that the communication with the outside trans-
mission antenna assembly (tailgate) is normal (Refer 
to Antenna Test 

P.42B-89

).

Antennas to be checked

• Tailgate antenna (outdoor)

OK: Normal is displayed.

Q: Is the check result normal?

YES : 

Go to Step 3

NO : 

Replace the outside transmission antenna 
assembly (tailgate).

STEP 3. Check whether the diagnosis code is 
reset.
(1) Erase the diagnosis code.
(2) Turn the power supply mode of the engine switch 

from OFF to ON.

(3) Check if the diagnosis code is set.
(4) Turn the power supply mode of the engine switch 

from OFF to ON.

Q: Is the diagnosis code set?

YES : 

Replace KOS-ECU and register the ID 

codes (Refer to 

P.42B-88

).

NO : 

Intermittent malfunction is suspected (Refer 
to GROUP 00 

− How to Use 

Troubleshooting/Inspection Service Points 

− 

How to Deal with Intermittent Malfunction ).

Code No.B240D Front antenna(indoor) open

CAUTION

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

DIAGNOSTIC FUNCTION

If an open circuit is detected in the inside transmis-
sion antenna (front), the diagnosis code is set.

JUDGMENT CRITERIA

While the engine switch is turned to the OFF posi-
tion, the system has detected an open circuit in the 
antenna.

PROBABLE CAUSES

• Malfunction of the inside transmission antenna 

assembly (front)

• Malfunction of the KOS-ECU

• Damaged wiring harness and connectors

DIAGNOSIS PROCEDURE

STEP 1. Check of short to power supply, short to 
earth, and open circuit in INFP, INFG line between 
the inside transmission antenna assembly (front) 
connector and the KOS-ECU connector.

Q: Is the check result normal?

YES : 

Go to Step 2

NO : 

Repair the connectors or wiring harness.

TROUBLESHOOTING <KOS-ECU>

KEYLESS OPERATION SYSTEM (KOS)

42B-24

STEP 2. Keyless operation system 
communication test
Check that the communication with the inside trans-
mission antenna assembly (front) is normal (Refer to 
Antenna Test 

P.42B-89

).

Antennas to be checked
Front antenna (indoor)

OK: Normal is displayed.

Q: Is the check result normal?

YES : 

Go to Step 3

NO : 

Replace the inside transmission antenna 
assembly (front).

STEP 3. Check whether the diagnosis code is 
reset.
(1) Erase the diagnosis code.
(2) Turn the power supply mode of the engine switch 

from OFF to ON.

(3) Check if the diagnosis code is set.
(4) Turn the power supply mode of the engine switch 

from OFF to ON.

Q: Is the diagnosis code set?

YES : 

Replace KOS-ECU and register the ID 

codes (Refer to 

P.42B-88

).

NO : 

Intermittent malfunction is suspected (Refer 
to GROUP 00 

− How to Use 

Troubleshooting/Inspection Service Points 

− 

How to Deal with Intermittent Malfunction ).

Code No.B240E RR antenna(indoor) open

CAUTION

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

DIAGNOSTIC FUNCTION

If an open circuit is detected in the inside transmis-
sion antenna (rear), the diagnosis code is set.

JUDGMENT CRITERIA

While the engine switch is turned to the OFF posi-
tion, the system has detected an open circuit in the 
antenna.

PROBABLE CAUSES

• Malfunction of the inside transmission antenna 

assembly (rear)

• Malfunction of the KOS-ECU

• Damaged wiring harness and connectors

DIAGNOSIS PROCEDURE

STEP 1. Check of short to power supply, short to 
earth, and open circuit in INRP, INRG line 
between the inside transmission antenna 
assembly (rear) connector and the KOS-ECU 
connector.

Q: Is the check result normal?

YES : 

Go to Step 2

NO : 

Repair the connectors or wiring harness.

STEP 2. Keyless operation system 
communication test
Check that the communication with the inside trans-
mission antenna assembly (rear) is normal (Refer to 
Antenna Test 

P.42B-89

).

Antennas to be checked
Rear antenna (indoor)

OK: Normal is displayed.

Q: Is the check result normal?

YES : 

Go to Step 3

NO : 

Replace the inside transmission antenna 
assembly (rear).

STEP 3. Check whether the diagnosis code is 
reset.
(1) Erase the diagnosis code.
(2) Turn the power supply mode of the engine switch 

from OFF to ON.

(3) Check if the diagnosis code is set.
(4) Turn the power supply mode of the engine switch 

from OFF to ON.

Q: Is the diagnosis code set?

YES : 

Replace KOS-ECU and register the ID 

codes (Refer to 

P.42B-88

).

NO : 

Intermittent malfunction is suspected (Refer 
to GROUP 00 

− How to Use 

Troubleshooting/Inspection Service Points 

− 

How to Deal with Intermittent Malfunction ).