Mitsubishi Galant (2004+). Manual - part 1276

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-797

STEP 1. Using scan tool MB991958, read the immobilizer 
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 immobilizer-DTC.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the immobilizer-DTC set?

YES : Refer to GROUP 54A, Ignition Switch and 

Immobilizer System 

− Diagnostic Trouble Code Chart 

P.54A-13

.

NO :  If DTC P0513 is output again after the MFI-DTC has 

been erased, replace the PCM. Then check that the 
DTC P0513 does not reset.

DTC P0551: Power Steering Pressure Switch Circuit Range/Performance

AC305412

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

AK302866

YELLO

W

POWERTRAIN
CONTROL
MODULE (PCM)

1

B-31

(MU801211)

POWER STEERING
PRESSURE SWITCH

78

1

Power Steering Pressure Switch Circuit

B-21

52

51

53 54 55 56

57

58 59 60 61 62

63

64 65 66 67 68 69

70

71 72 73 74 75

76

77 78 79 80 81 82

83

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-798

.

CIRCUIT OPERATION

• A battery positive voltage is applied to the power 

steering pressure switch output terminal (terminal 
No. 1) from the PCM (terminal No. 78) via the 
resistor in the PCM.

.

TECHNICAL DESCRIPTION

• The power steering pressure switch converts the 

existence of a power steering load into a high/low 
voltage, and inputs it into the PCM.

• When the steering wheel is turned, hydraulic 

pressure rises. The power steering pressure 
switch closes, and the applied battery positive 
voltage will be grounded. With this, the power 
steering pressure switch output voltage will fluc-
tuate between 0 and 12 volts.

• While driving with the steering wheel held 

straight, the power steering pressure switch turns 
"OFF".

• The PCM checks whether the power steering 

pressure switch turns "OFF" or "ON" during driv-
ing.

.

DESCRIPTIONS OF MONITOR METHODS
Power steering pressure switch stays on during 

specified go/stop operations.

.

MONITOR EXECUTION
Continuous

.

MONITOR EXECUTION CONDITIONS (Other 
monitor and Sensor)

Other Monitor (There is no temporary DTC stored 

in memory for the item monitored below)

• Not applicable

Sensor (The sensor below is determined to be 

normal)

• Engine coolant temperature sensor

.

AK303161

AB

POWER STEERING
PRESSURE SWITCH

B-31 (B)

CONNECTOR: B-31

AK303119

CONNECTOR: B-21

PCM

AB

AIR CLEANER

B-21

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-799

DTC SET CONDITIONS

Logic Flow Chart

.

Check Conditions 

• Engine coolant temperature is higher than 30°C 

(86

°F). 

• Drive for 4 seconds or more with the vehicle 

speed is 50 km/h (31 mph) or more. Stop the 
vehicle [vehicle speed is 1.5 km/h (1.0 mph) or 
less]. Repeat 10 times or more. 

Judgment Criteria 

• Power steering pressure switch continues to be 

"ON". 

.

OBD-II DRIVE CYCLE PATTERN
None.

.

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

• Power steering pressure switch failed. 

• Open or shorted power steering pressure switch 

circuit, harness damage, or connector damage. 

• PCM failed.

YES

NO

NO

NO

MONITORING

CONDITIONS

END

MALFUNCTION

GOOD

START

POWER STEERING

SWITCH = "ON"

YES

GO/STOP OPERATION

FOR SPECIFIED TIMES

YES

AK302409

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-800

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, check data list item 27: 
Power Steering Pressure Switch. 

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) Start the engine and run at idle. 

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

27, Power Steering Pressure Switch. 

• If the steering wheel is not turned  while idling, "OFF" 

will be displayed.

• If the steering wheel is turned while idling, "ON" will be 

displayed.

(4) Turn the ignition switch to the "LOCK" (OFF) position. 
Q: Is the switch 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 :  Go to Step 2.

AC305412

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827