Mitsubishi Galant (2004+). Manual - part 1317

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-961

CAUTION

When the ignition key is maintained within the 
range "A" (i.e., the ignition switch IG2 is in OFF 
poition but the cranking does not  start) for more 
than 1 second, PCM stores DTC U1110 (the past 
trouble).
NOTE: If a malfunction occurred in the past, a failure 
cannot be discovered through the MB991958 CAN 
bus diagnosis even if there might be a problem with 
the CAN bus. In this case, refer to GROUP 00, How 
to Use Troubleshooting/Inspection Service 

Points-How to Cope with Intermittent Malfunction 

P.00-6

. Furthermore, it is possible to narrow down 

the areas of the possible failures from the DTCs that 
are output by the ECUs, which are communicating 
on the CAN bus (Refer to GROUP 54C, CAN bus 
line Diagnostics Flow 

P.54C-6

).

.

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

• CAN line harness damage or connector damage.

• A/C-ECU failed.

• PCM failed.

DIAGNOSIS

Required Special Tools:

• MB991958: Scan tool (MUT-III Sub Assembly)

• MB991824: V.C.I.

• MB991827: USB Cable

• MB991910: Main Harness A

STEP 1. Using scan tool MB991958, diagnose 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 to the data link connector.
(2) Turn the ignition switch to the "ON" position.

(3) Diagnose CAN bus line.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the CAN bus line normal?

YES : Go to Step 2.
NO :  Repair the CAN bus line. Refer to GROUP 54C, Can 

Bus Diagnostics Table 

P.54C-14

. Then go to Step 6.

AK204418 AB

ACC POSITION

LOCK (OFF) 
POSITION

ON POSITION

START
POSITION

RANGE 
"A"

AC305412

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-962

STEP 2. Using scan tool MB991958, read the diagnostic 
trouble code (DTC).

(1) Connect scan tool MB991958 to the data link connector.
(2) Turn the ignition switch to the "ON" position.

(3) Read the A/C-DTC.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the A/C-DTC set?

YES : Refer to GROUP 55B, Auto A/C Diagnosis 

− 

Diagnostic Trouble Code Chart 

P.55B-8

.

NO :  Go to Step 3.

STEP 3. Using scan tool MB991958, read the diagnostic 
trouble code (DTC).

(1) Connect scan tool MB991958 to the data link connector.
(2) Turn the ignition switch to the "ON" position.

(3) Read the combination ETACS-DTC.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is DTC 012 set?

YES : Go to Step 4.
NO :  Go to Step 5.

AC305412

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

AC305412

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-963

STEP 4. Using scan tool MB991958, read the diagnostic 
trouble code (DTC).

(1) Connect scan tool MB991958 to the data link connector.
(2) Turn the ignition switch to the "ON" position.
(3) After the MFI-DTC has been deleted, read the MFI-DTC 

again.

(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is DTC U1110 set?

YES : Replace the A/C-ECU. Then go to Step 6.
NO :  It can be assumed that this malfunction is intermittent 

of CAN bus line between PCM and A/C-ECU. Refer to 
GROUP 00, How to Use Troubleshooting/Inspection 
Service Points 

P.00-6

.

STEP 5. Using scan tool MB991958, read the diagnostic 
trouble code (DTC).

(1) Connect scan tool MB991958 to the data link connector.
(2) Turn the ignition switch to the "ON" position.

(3) After the MFI-DTC has been deleted, read the MFI-DTC 

again.

(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is DTC U1110 set?

YES : Replace the PCM. Then go to Step 6.
NO :  It can be assumed that this malfunction is intermittent 

of CAN bus line between PCM and A/C-ECU. Refer to 
GROUP 00, How to Use Troubleshooting/Inspection 
Service Points 

P.00-6

.

AC305412

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

AC305412

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-964

STEP 6. Using scan tool MB991958, read the diagnostic 
trouble code (DTC).

(1) Connect scan tool MB991958 to the data link connector.
(2) Turn the ignition switch to the "ON" position.
(3) After the MFI-DTC has been deleted, read the MFI-DTC 

again.

(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is DTC U1110 set?

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

AC305412

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

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