Mitsubishi Galant (2004+). Manual - part 1314

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-949

STEP 1. Using scan tool MB991958, check data list item 25: 
Barometric Pressure Sensor.

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) Set scan tool MB991958 to the data reading mode for item 

25, Barometric Pressure Sensor.

• When altitude is 0 m (0 foot), 101 kPa (29.8 In.Hg).

• When altitude is 600 m (1,969 feet), 95 kPa (28.1 

In.Hg).

• When altitude is 1,200 m (3,937 feet), 88 kPa (26.0 

In.Hg).

• When altitude is 1,800 m (5,906 feet), 81 kPa (23.9 

In.Hg).

(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the sensor operating properly?

YES : It can be assumed that this malfunction is intermittent. 

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

P.00-6

.

NO :  Replace the PCM, then go to Step 2.

STEP 2. 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 − Procedure 6 − 

Other Monitor 

P.13B-5

.

(2) Check the diagnostic trouble code (DTC).
Q: Is DTC P2229 set?

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

DTC U1073: Bus Off

CAUTION

• If the PCM output the DTC U1073, make sure 

to diagnose the CAN bus line.

• Before replacing the ECU, make sure that the 

communication circuit is operating normally.

.

DTC SET CONDITIONS

Check Conditions

• Always

Judgement Criteria

• Bus off error detected

.

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

• CAN line harness damage or connector damage.

• PCM failed.

AC305412

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-950

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 san 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 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 3.

STEP 2. Recheck for diagnostic trouble code.

Check again if the DTC is set.
(1) Erase the DTC.
(2) Turn the ignition switch to the "ON" position.

(3) Check if the DTC is set.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is DTC U1073 set?

YES : Replace the PCM. Then go to Step 3.
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 Malfunction 

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-951

STEP 3. Recheck for diagnostic trouble code.

Check again if the DTC is set.
(1) Erase the DTC.
(2) Turn the ignition switch to the "ON" position.

(3) Check if DTC is set.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is DTC U1073 set?

YES : Go to Step 1.
NO :  The procedure is complete.

DTC U1102: ABS-ECU TIME-OUT

CAUTION

• If the PCM output the DTC U1102, make sure 

to diagnose the CAN bus line.

• Before replacing the ECU, make sure that the 

communication circuit is operating normally.

.

DTC SET CONDITIONS

Check Conditions

• Battery positive voltage is 10 volts or higher.

• Engine is not cranked, or at least 3 seconds have 

passed since engine was cranked.

Judgement Criteria

• Unable to receive ABS-ECU signals through the 

CAN bus line.

.

COMMENT

Current Trouble

• Some of the possible causes are a harness or 

connector damage between the PCM and the 
ABS-ECU on the CAN bus line, a failure in the 
ABS-ECU power supply system, a failure in the 
ABS-ECU, or a failure in the PCM.

Past Trouble

• Proceed to troubleshoot based on a harness or 

connector damage on the CAN bus line between 
the PCM and ABS-ECU, and a failure in the ABS 
power supply system. Refer to "How to cope with 
past trouble" (Refer to GROUP 00, How to Use 
Troubleshooting/Inspection Service Points). 

P.00-6

).

AC305412

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-952

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 U1102 (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.

• ABS-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