Mitsubishi Evolution X. Manual - part 617

DIAGNOSIS

TSB Revision

WIRELESS CONTROL MODULE (WCM)

42C-85

SYMPTOM PROCEDURES

Inspection Procedure 1: Scan tool cannot communicate with WCM.

CAUTION

Before replacing the ECU, ensure that the com-
munication circuit is normal.

.

TECHNICAL DESCRIPTION (COMMENT)

If the M.U.T.-III cannot communicate with the WCM, 
the CAN bus lines may be defective. If the WCM 
does not work, the WCM or the power supply circuit 
may be defective.

.

TROUBLESHOOTING HINTS

• Malfunction of the power supply or ground of 

WCM

• Malfunction of CAN bus line

• 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 con-
necting or disconnecting scan tool MB991958.
(1) Connect scan tool MB991958. Refer to "How to connect the 

Scan Tool (M.U.T.-III) 

P.42C-6

."

(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

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WIRELESS CONTROL MODULE (WCM)

42C-86

STEP 2. Check the power supply circuit and the ground 
circuit to WCM.
Refer to Inspection Procedure 4 "Abnormality in WCM power 
supply and ground circuits." 

P.42C-90

.  

Q: Is the power supply circuit and the ground circuit to 

WCM in good condition ?
YES : Go to Step 3.
NO :  Repair the power supply circuit and the ground circuit 

to WCM.

STEP 3. Retest the system
Check if scan tool can communicate with WCM.
Q: Does the scan tool communicate with WCM?

YES : 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

).

NO :  Replace WCM and register the ID codes (Refer to 

P.42C-9

).

Inspection Procedure 2: The ignition key cannot be registered using scan tool.

.

TECHNICAL DESCRIPTION (COMMENT)

If only some ignition keys cannot be registered, the 
ignition key itself may be faulty. If no ignition key can 
be registered, the key assembly may have already 
been registered for another vehicle, or the WCM may 
be faulty.

.

TROUBLESHOOTING HINTS

• Malfunction of the ignition key

• Damaged wiring harness and connectors

• Malfunction of WCM

• 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

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

NO :  Go to Step 3.

DIAGNOSIS

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WIRELESS CONTROL MODULE (WCM)

42C-87

STEP 2. Retest the system
Check that the ignition key can be registered.
Q: Is the ignition key that cannot be registered using scan 

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

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

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

registered and register the ID codes (Refer to 

P.42C-9

). After registering the ID codes, go to Step 5 .

NO (All keys) : Go to Step 4.

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.42C-23

 <B1A25>, 

P.42C-27

 <B1A35>). 

Then, go to Step 5 . 

NO (ECU internal error) : Replace WCM and register the 

ID codes (Refer to 

P.42C-9

).

STEP 5. Retest the system
Check that the ignition key can be registered.
Q: Is the ignition key that cannot be registered using scan 

tool?
YES : Replace WCM and register the ID codes (Refer to 

P.42C-9

).

NO :  The procedure is complete.

DIAGNOSIS

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WIRELESS CONTROL MODULE (WCM)

42C-88

Inspection Procedure 3: Engine does not start (cranking but no initial combustion).

.

TECHNICAL DESCRIPTION (COMMENT)

If the fuel injection does not work, WCM and the MFI 
system may have a problem. This symptom is not 
considered abnormal when the engine is started by 
an ignition key that has not been registered.

.

TROUBLESHOOTING HINTS

• Malfunction of battery

• Malfunction of the MFI system

• Malfunction of WCM

• Malfunction of CAN bus line

• Malfunction of the transponder

• VIN not programmed

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. Check the battery voltage.
Measure the battery voltage when cranking.

• The voltage should measure 8 volt or more.

Q: Is the measured voltage 8 volt or more?

YES : Go to Step 2.
NO :  Check the battery (Refer to GROUP 54A 

− Battery test 

P.54A-9

).

STEP 2. 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 con-
necting or disconnecting scan tool MB991958.
(1) Connect scan tool MB991958. Refer to "How to connect the 

Scan Tool (M.U.T.-III) 

P.42C-6

."

(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 3.
NO :  Repair the CAN bus line (Refer to GROUP 54C, 

Diagnosis 

P.54C-14

).

AC608435

Data link connector

MB991827

MB991824

MB991910

AB