Mitsubishi Colt Ralliart. Manual — part 713

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI) <4G1>

13B-177

Code No. P0642: Throttle Position Sensor Power Supply

FUNCTION

• Engine-ECU checks the throttle position sensor

power voltage for abnormal conditions.

TROUBLE JUDGMENT

Check Conditions

• Ignition switch is in "ON" position.

• Battery positive voltage is more than 6.3 V.

Judgement Criteria

• Throttle position sensor power voltage is less

than 4.1 V.

PROBALE CAUSE

• Failed engine-ECU <M/T>

DIAGNOSIS

STEP 1. Check the trouble symptoms.

Q: Does trouble symptom persist?

YES :

Replace engine-ECU.

NO :

Intermittent malfunction (Refer to GROUP
00

− How to Use

Troubleshooting/Inspection Service Points

−

How to Cope with Intermittent Malfunctions

P.00-13

).

Main

Index

Group

TOC

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI) <4G1>

13B-178

Code No. P0657: Throttle Valve Control Servo Relay Circuit Malfunction

OPERATION

• Battery voltage is applied to the throttle valve

control servo relay terminal (terminal No. 3).

• Battery voltage is applied to the throttle valve

control servo relay terminal (terminal No. 1) from
the engine control relay (terminal No. 4).

• Engine-ECU (terminal No. 123) applies current to

the throttle valve control servo relay coil by turn-
ing ON the power transistor in the unit in order to
turn the relay ON.

• When the throttle valve control servo relay turns

ON, battery voltage is supplied by the throttle
valve control servo relay (terminal No. 4) to the
engine-ECU (terminal No. 78).

AK503598

3

1

2

4

3

1

2

4

R

92 93 94 95969798

77 78 79 808182838485868788899091

99

100

107 108 109 110 111112113114115116117118119120121
122 123 124 125126127128129130131132133134135136

101102103104105106

71 72

73 74

75 76

AD

Power source

L-W

R-L

Wire colour code
B: Black LG: Light green G: Green L: Blue W: White Y: Yellow SB: Sky blue BR: Brown O: Orange GR: Gray
R: Red P: Pink V: Violet

P: Purple

Engine-ECU

Throttle Valve Control Servo Relay Circuit

Engine
control
relay

Throttle
valve
control
servo
relay

B-106

B-121

B-108

3

1

4

2

3

1

32

B-112

B-110

5

78

123

4

2

1

1

R

Fusible link

16

20A

J/B

To engine-ECU

A-08

Main

Index

Group

TOC

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI) <4G1>

13B-179

FUNCTION

• When the ignition switch ON signal is input into

the engine-ECU, the engine-ECU turns ON the
throttle valve control servo.

TROUBLE JUDGMENT

Check Condition

• After engine starts

Judgement Criterions

• Throttle valve control servo supply voltage is less

than 6.0 V.

• Battery voltage is more than 8.3 V.

PROBALE CAUSES

• Failed throttle valve return spring

• Open/short circuit and damage in throttle valve

control servo circuit or loose connector contact.

• Failed engine-ECU

DIAGNOSIS PROCEDURE

STEP 1. Connector check: B-121 throttle valve
control servo relay connector

Q: Is the check result normal?

YES :

Go to Step 2 .

NO :

Repair or replace the connector.

STEP 2. Check throttle valve control servo relay
itself.

• Check throttle valve control servo relay (Refer to

P.13B-364

).

Q: Is the check result normal?

YES :

Go to Step 3 .

NO :

Replace the throttle valve control servo
relay.

STEP 3. Perform voltage measurement at B-121
throttle valve control servo relay connector.

• Remove relay, and measure at J/B side.

• Voltage between terminal No. 3 and earth.

OK: System voltage

Q: Is the check result normal?

YES :

Go to Step 4 .

NO :

Check intermediate connector B-208, and

repair if necessary. If intermediate
connector is normal, Check and repair
harness between B-121 (terminal No. 3)
throttle valve control servo relay connector
and battery.

• Check power supply line for

open/short circuit.

AK402100

3

2

1

4

AC

Connector: B-121

J/B side
connector

B-121

AK402100

3

2

1

4

AC

Connector: B-121

J/B side
connector

B-121

Main

Index

Group

TOC

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI) <4G1>

13B-180

STEP 4. Perform voltage measurement at B-121
throttle valve control servo relay connector.

• Remove relay, and measure at J/B side.

• Ignition switch: ON

• Voltage between terminal No. 1 and earth.

OK: System voltage

Q: Is the check result normal?

YES :

Go to Step 6 .

NO :

Go to Step 5 .

STEP 5. Connector check: B-106 engine control
relay connector

AK402100

3

2

1

4

AC

Connector: B-121

J/B side
connector

B-121

3

2

1

4

AK402084

J/B side
connector

B-106

Connector: B-106
J/B (front side)

AC

AK402100

3

2

1

4

AC

Connector: B-121

J/B side
connector

B-121

Main

Index

Group

TOC