Mitsubishi Galant 9G. Manual — part 1149

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-896

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

AK400896

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) <3.8L ENGINE>

13B-897

.

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. 1).

• 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. 1) 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.

.

DTC SET CONDITIONS

Check Condition

• Battery positive voltage is higher than 8.3 volts.

Judgement Criteria

• The power line voltage of the electronic controlled

throttle system should be 6.0 volts or less for 0.35
seconds.

.

AK303148

CONNECTOR: A-13

AB

A-13(GR)

1

2

3

4

1

2

3

4

1

2

3

4

1

2

3

4

AK303014

CONNECTOR: B-17X

MFI RELAY

MFI RELAY

FRONT OF VEHICLE

B-17X

AB

1

2

3

4

1

2

3

4

1

2

3

4

1

2

3

4

AK303173

CONNECTOR: B-14X

MFI RELAY

MFI RELAY

FRONT OF VEHICLE

B-14X

AB

AK303059

CONNECTOR: B-23

PCM

AB

AIR CLEANER

B-23

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-898

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

• Throttle actuator control motor relay failed or mal-

adjusted.

• Open or shorted throttle actuator control motor

relay circuit, or loose connector.

• 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. Check harness connector B-14X at throttle
actuator control motor relay for damage.
Q: Is the harness connector in good condition?

YES : Go to Step 2.
NO : Repair or replace it. Refer to GROUP 00E, Harness

Connector Inspection

P.00E-2

. Then go to Step 14.

1

2

3

4

AK303175

CONNECTOR: B-14X

FRONT OF VEHICLE

B-14X

AB

HARNESS
CONNECTOR:
COMPONENT SIDE

RELAY BOX

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

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MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-899

STEP 2. Check the throttle actuator control motor relay.

CAUTION

Because it is not possible to distinguish the top and the
bottom of the throttle actuator control motor relay, inspect
with the triangle mark printed on the relay facing upward.
(1) Remove the throttle actuator control motor relay.

(2) Check for continuity between the throttle actuator control

motor relay terminal No. 2 and No. 3.

• There should be continuity (approximately 70 ohms).

(3) Use jumper wires to connect throttle actuator control motor

relay terminal No. 2 to the positive battery terminal and
terminal No. 3 to the negative battery terminal.

(4) Check the continuity between the throttle actuator control

motor relay terminal No. 1 and No. 4 while connecting and
disconnecting the jumper wire at the negative battery
terminal.

• Should be less than 2 ohms. (Negative battery terminal

connected.)

• Should be open loop. (Negative battery terminal discon-

nected.)

(5) Install the throttle actuator control motor relay.
Q: Is the measured resistance normal?

YES : Go to Step 3.
NO : Replace the throttle actuator control motor relay.

Then go to Step 14.

1

2

3

4

AK303175

CONNECTOR: B-14X

FRONT OF VEHICLE

B-14X

AB

HARNESS
CONNECTOR:
COMPONENT SIDE

RELAY BOX

AK303205

1

2

3

4

AB

THROTTLE ACTUATOR
CONTROL MOTOR RELAY
SIDE CONNECTOR

1

2

3

4

AK303193

THROTTLE ACTUATOR
CONTROL MOTOR RELAY
SIDE CONNECTOR

AE