Mitsubishi Lancer Evolution X. Manual - part 383

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-597

STEP 4. Check the throttle actuator control motor.
(1) Disconnect the connector B-11.
(2) Measure the resistance between throttle actuator control 

motor side connector terminal No. 1 and No. 2.

Standard value: 0.3 − 80 Ω [at 20° C (68° C)]

Q: Is the measured resistance between 0.3 and 80 Ω [at 

20° C (68° C)?
YES : Go to Step 5.
NO :  Replace the throttle body assembly. Then go Step 9.

STEP 5. Check for harness damage between throttle 
actuator control motor connector B-11 (terminal No. 1) and 
PCM connector B-09 (terminal No. 15).
Q: Is the harness wire in good condition?

YES : Go to Step 6.
NO :  Repair it. Then go to Step 9.

STEP 6. Check for harness damage between throttle 
actuator control motor connector B-11 (terminal No. 2) and 
PCM connector B-09 (terminal No. 16).
Q: Is the harness wire in good condition?

YES : Go to Step 7.
NO :  Repair it. Then go to Step 9.

STEP 7. Check for intake system vacuum leak.
Q: Are there any abnormalities?

YES : Repair it. Then go to Step 9. 
NO :  Go to Step 8.

STEP 8. Check the trouble symptoms.
(1) Carry out a test drive with the drive cycle pattern. Refer to 

Diagnostic Function − OBD-II Drive Cycle − Pattern 16 

P.13A-9

.

(2) Check the diagnostic trouble code (DTC).
Q: Is DTC P1241 set?

YES : Replace the ECM. When the ECM is replaced, 

register the ID code. Refer to GROUP 42B, ID Code 
Registration Necessity Judgment Table <Vehicles 
with KOS> 

P.42B-11

 or GROUP 42C, ID Codes 

Registration Judgment Table <Vehicles with WCM> 

P.42C-9

. Then go to Step 9.

NO :  It can be assumed that this malfunction is intermittent. 

Refer to GROUP 00, How to Use 
Troubleshooting/Inspection Service Points − How to 

Cope with Intermittent Malfunctions 

P.00-15

. 

6

1 2 3 4 5

AK604495AB

Throttle actuator control 
motor connector

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-598

STEP 9. Test the OBD-II drive cycle.
(1) Carry out a test drive with the drive cycle pattern. Refer to 

Diagnostic Function − OBD-II Drive Cycle − Pattern 16 

P.13A-9

.

(2) Check the diagnostic trouble code (DTC).
Q: Is DTC P1241 set?

YES : Retry the troubleshooting.
NO :  The inspection is complete.

DTC P1242: Fail Safe Control Monitor

.

TECHNICAL DESCRIPTION

Monitors the engine speed during fail-safe control.

.

DTC SET CONDITIONS

Check Condition

• During fail safe control.

Judgment Criterion

• The engine speed is higher than assumed.

.

FAIL-SAFE AND BACKUP FUNCTION

• Throttle opening degree position is in default 

position.

.

TROUBLESHOOTING HINTS (The most 
likely causes for this code to be set are:)

• ECM failed.

DIAGNOSIS

Required Special Tools:

• MB991958: Scan Tool (M.U.T.-III Sub Assembly)

• MB991824: V.C.I.
• MB991827: USB Cable
• MB991910: Main Harness A

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-599

STEP 1. Using scan tool MB991958, read the diagnostic 
trouble code (DTC).

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 to the data link connector.
(2) Turn the ignition switch to the "ON" position.
(3) Read the DTC.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the diagnostic trouble code other than P1242 set?

YES : Refer to, Diagnostic Trouble Code Chart 

P.13A-48

. 

NO :  Go to Step 2 . 

STEP 2. Using scan tool MB991958, read the diagnostic 
trouble code (DTC).
(1) Turn the ignition switch to the "ON" position.
(2) After the DTC has been deleted, read the DTC again.
(3) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is DTC P1242 set?

YES : Replace the ECM. When the ECM is replaced, 

register the ID code. Refer to GROUP 42B, ID Code 
Registration Necessity Judgment Table <Vehicles 
with KOS> 

P.42B-11

 or GROUP 42C, ID Codes 

Registration Judgment Table <Vehicles with WCM> 

P.42C-9

.

NO :  It can be assumed that this malfunction is intermittent. 

Refer to GROUP 00, How to Use 
Troubleshooting/Inspection Service Points − How to 

Cope with Intermittent Malfunctions 

P.00-15

.

AC608435

Data link connector

MB991827

MB991824

MB991910

AB

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-600

DTC P1243: Inquiry/Response Error

.

TECHNICAL DESCRIPTION

Monitors the computation function of the ECM.

.

DTC SET CONDITIONS

Check Condition

• Ignition switch is "ON" position.

Judgment Criterion

• ECM can not calculate input data.

.

FAIL-SAFE AND BACKUP FUNCTION

• Microcomputer is reset.

.

TROUBLESHOOTING HINTS (The most 
likely causes for this code to be set are:)

• ECM failed.

DIAGNOSIS

Required Special Tools:

• MB991958: Scan Tool (M.U.T.-III Sub Assembly)

• MB991824: V.C.I.
• MB991827: USB Cable
• MB991910: Main Harness A

STEP 1. Using scan tool MB991958, read the diagnostic 
trouble code (DTC).

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 to the data link connector.
(2) Turn the ignition switch to the "ON" position.
(3) Read the DTC.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is DTC P1243 set?

YES : Replace the ECM. When the ECM is replaced, 

register the ID code. Refer to GROUP 42B, ID Code 
Registration Necessity Judgment Table <Vehicles 
with KOS> 

P.42B-11

 or GROUP 42C, ID Codes 

Registration Judgment Table <Vehicles with WCM> 

P.42C-9

.

NO :  It can be assumed that this malfunction is intermittent. 

Refer to GROUP 00, How to Use 
Troubleshooting/Inspection Service Points − How to 

Cope with Intermittent Malfunctions 

P.00-15

.

AC608435

Data link connector

MB991827

MB991824

MB991910

AB