Mitsubishi Galant (2004+). Manual - part 993

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L ENGINE>

13A-789

DTC P0642: Throttle Position Sensor Power Supply

.

TECHNICAL DESCRIPTION

• PCM checks the throttle position sensor power 

voltage for abnormal conditions.

.

DESCRIPTIONS OF MONITOR METHODS
Throttle position sensor source voltage is smaller 

than the specified value.

.

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)

• Not applicable

.

DTC SET CONDITIONS

Check Conditions

• Battery positive voltage is higher than 6.3 volts.

Judgement Criteria

• Throttle position sensor power voltage should be 

4.1 volts or less for 0.5 second.

.

OBD-II DRIVE CYCLE PATTERN
None.

.

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

• PCM failed.

DIAGNOSIS

Required Special Tools:

• MB991958: Scan tool (MUT-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) <2.4L ENGINE>

13A-790

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) After the DTC has been deleted, read the DTC again.
(4) Turn the ignition switch to the "LOCK"(OFF) position.
Q: Is DTC P0642 set?

YES : Replace the PCM.
NO :  It can be assumed that this malfunction is intermittent. 

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

P.00-6

.

AK303804AB

MB991910

DATA LINK
CONNECTOR

MB991824

MB991827

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L ENGINE>

13A-791

DTC P0657: Throttle Actuator Control Motor Relay Circuit Malfunction

CAUTION

If DTC P0657 has been set, TCL related DTC 
U1120 is also set. After P0657 has been diag-
nosed, don't forget to erase DTC U1120.

1

2

3

4

1

2

3

4

1 2

3 4 5

14

15

8 9

12 13

6 7

10 11
16 17

AK303885

121 122 123 124 125 126 127

128 129 130 131 132 133

134 135 136 137 138 139 140

141 142 143 144 145 146

147 148 149 150 151 152 153

THROTTLE ACTUATOR
CONTROL MOTOR RELAY

THROTTLE ACTUATOR
CONTROL MOTOR
POWER SOURCE

B-17X

B-14X

A-13

RED-BLUE

RED-

WHITE

RED-

WHITE

RED-

WHITE

RED-
WHITE

BLUE-WHITE

TO PCM

TO PCM

MFI
RELAY

RED

RED

RED

BATTERY

Throttle Actuator Contorol Motor Relay Circuit

2

1

5

3

4

2

1

3

4

123

122

POWERTRAIN CONTROL MODULE (PCM)

B-23

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L ENGINE>

13A-792

.

CIRCUIT OPERATION

• Battery positive voltage is applied to the throttle 

actuator control motor relay terminal (terminal 
No. 1).

• Battery positive voltage is applied to the throttle 

actuator control motor relay terminal (terminal 
No. 2) from the MFI relay (terminal No. 4).

• PCM (terminal No. 123) applies current to the 

throttle actuator control motor relay coil by turning 
ON the power transistor in the unit in order to turn 
the relay ON.

• When the throttle actuator control motor relay 

turns ON, battery positive voltage is supplied by 
the throttle actuator control motor relay (terminal 
No. 4) to the PCM (terminal No. 122).

.

TECHNICAL DESCRIPTION

• When the ignition switch ON signal is input into 

the PCM, the PCM turns ON the throttle actuator 
control motor relay.

.

DESCRIPTIONS OF MONITOR METHODS
Throttle actuator control motor relay circuit voltage is 

smaller than the specified value.

.

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)

• Not applicable

.

DTC SET CONDITIONS

Check Condition

• Ignition switch is "ON" position.

Judgement Criteria

• The power line voltage of the electronic controlled 

throttle valve system should be 4.0 volts or less 
for 1 second.

.

AK303872AB

A-13 (GR)

CONNECTOR: A-13

AK303886AB

CONNECTOR: B-14X

THROTTLE 
ACTUATOR
CONTROL 
MOTOR RELAY

B-14X

AK303803AB

CONNECTOR: B-17X

MFI RELAY

B-17X

AK303059

CONNECTOR: B-23

PCM

AB

AIR CLEANER

B-23