Mitsubishi Evolution X. Manual - part 601

DIAGNOSIS

TSB Revision

WIRELESS CONTROL MODULE (WCM)

42C-21

DTC B1A10: Keyless/KOS key 1 low battery

 

DTC B1A11: Keyless/KOS key 2 low battery

 

DTC B1A12: Keyless/KOS key 3 low battery

 

DTC B1A13: Keyless/KOS key 4 low battery

 

DTC B1A14: Keyless key 5 low battery

 

DTC B1A15: Keyless key 6 low battery

 

DTC B1A16: Keyless key 7 low battery

 

DTC B1A17: Keyless key 8 low battery

CAUTION

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

.

DTC SET CONDITION

WCM sets DTC B1A10, B1A11, B1A12, B1A13, 
B1A14, B1A15, B1A16, or B1A17 when it receives 
low battery voltage signal from the transmitter.

.

TECHNICAL DESCRIPTION (COMMENT)

• B1A10: WCM determines that the abnormality is 

present when it receives low battery voltage sig-
nal from the transmitter 1 (the first transmitter 
registered in WCM) five consecutive times.

• B1A11: WCM determines that the abnormality is 

present when it receives low battery voltage sig-
nal from the transmitter 2 (the second transmitter 
registered in WCM) five consecutive times.

• B1A12: WCM determines that the abnormality is 

present when it receives low battery voltage sig-
nal from the transmitter 3 (the third transmitter 
registered in WCM) five consecutive times.

• B1A13: WCM determines that the abnormality is 

present when it receives low battery voltage sig-
nal from the transmitter 4 (the fourth transmitter 
registered in WCM) five consecutive times.

• B1A14: WCM determines that the abnormality is 

present when it receives low battery voltage sig-
nal from the transmitter 5 (the fifth transmitter 
registered in WCM) five consecutive times.

• B1A15: WCM determines that the abnormality is 

present when it receives low battery voltage sig-
nal from the transmitter 6 (the sixth transmitter 
registered in WCM) five consecutive times.

• B1A16: WCM determines that the abnormality is 

present when it receives low battery voltage sig-
nal from the transmitter 7 (the seventh transmitter 
registered in WCM) five consecutive times.

• B1A17: WCM determines that the abnormality is 

present when it receives low battery voltage sig-
nal from the transmitter 8 (the eighth transmitter 
registered in WCM) five consecutive times.

.

TROUBLESHOOTING HINTS

• Battery failure in the transmitter

• Malfunction of the transmitter

• Malfunction of WCM

DIAGNOSIS

STEP 1. Replace the battery in the transmitter 
and recheck the diagnostic trouble code.
Replace the battery in the transmitter by which the 
DTC is set with a new one, and recheck if the DTC is 
set (Refer to 

P.42C-129

).

(1) Replace the battery in the transmitter by which 

the DTC is set.

(2) Use the transmitter to lock/unlock the doors.
(3) Check if the DTC is set.

Q: Is the DTC set?

YES : 

Go to Step 2.

NO : 

The diagnosis is complete (Discharged 
battery).

STEP 2. Replace the transmitter and recheck the 
diagnostic trouble code.
Replace the transmitter by which the DTC is set with 
a new one, register the key ID and the keyless entry 
secret code (Refer to 

P.42C-114

), and recheck if the 

DTC is set.
(1) Use the transmitter to lock/unlock the doors.
(2) Check if the DTC is set.

Q: Is the DTC set?

YES : 

Replace WCM and register the ID codes 

(Refer to 

P.42C-9

).

NO : 

The diagnosis is complete.

DIAGNOSIS

TSB Revision

WIRELESS CONTROL MODULE (WCM)

42C-22

DTC B1A24: Key ID not registered

CAUTION

• When the DTC B1A24 is set, be sure to diag-

nose the CAN bus line.

• When replacing the ECU, always check that 

the communication circuit is normal.

.

DTC SET CONDITION

WCM sets DTC B1A24 when the key ID was not reg-
istered in it. 

.

TECHNICAL DESCRIPTION (COMMENT)

WCM determines that the abnormality is present, if 
the ignition key's key ID is not registered in WCM 
when the ignition switch is turned ON.

.

TROUBLESHOOTING HINTS

• Key ID not registered

• Malfunction of the ignition key

• Malfunction of WCM

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

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

WIRELESS CONTROL MODULE (WCM)

42C-23

STEP 2. Register the key ID and recheck the diagnostic 
trouble code.
Register the key ID of the ignition key (refer to 

P.42C-9

), and 

recheck if the DTC is set.
(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 WCM and register the ID codes (Refer to 

P.42C-9

).

NO :  The procedure is complete.

DTC B1A25: Key ID unmatched

CAUTION

When the DTC B1A25 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

WCM sets DTC B1A25 when the received key ID is 
different from the one registered in it. 

.

TECHNICAL DESCRIPTION (COMMENT)

WCM determines that the abnormality is present, if 
the key ID for the ignition key does not match the one 
registered in WCM when the ignition switch is turned 
ON.

.

TROUBLESHOOTING HINTS

• Malfunction of the ignition key

• Accessory key not registered

• Accessory WCM not registered

• Key is registered to another vehicle

• Malfunction of WCM

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

DIAGNOSIS

TSB Revision

WIRELESS CONTROL MODULE (WCM)

42C-24

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 key ID and recheck the diagnostic 
trouble code.
Register the key ID of the ignition key (refer to 

P.42C-9

), and 

recheck if the DTC is set.
(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 ignition key and recheck the 
diagnostic trouble code.
Replace the ignition key by which the DTC is set with  the other 
key, and recheck if the DTC is set.
(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 4.
NO :  Go to Step 5.

AC608435

Data link connector

MB991827

MB991824

MB991910

AB