Mitsubishi Galant 9G. Manual — part 1179

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-1016

INSPECTION PROCEDURE 2: Scan Tool Communication with PCM Is Not Possible.

ORANGE-BLUE

ORANGE-BLUE

AK400835

15

7

DATA LINK
CONNECTOR

13

POWERTRAIN
CONTROL
MODULE (PCM)

C-29

C-125

MU803797

Data Link Connector Circuit

B-19

1 2 3 4

5 6 7

8 9 10 11

12 13 14

15 16 17 18

AK303209AB

CONNECTOR: C-125

DATA LINK
CONNECTOR

C-125

ACCELERATOR
PEDAL

AK303147

CONNECTOR: B-19

PCM

AB

AIR CLEANER

B-19 (B)

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-1017

.

CIRCUIT OPERATION

• A diagnostic output is made from the PCM (termi-

nal No. 15) to the diagnostic output terminal (ter-
minal No. 7) of the data link connector.

.

COMMENT

• No power supply to PCM.

• Defective ground circuit of PCM.

• Defective PCM.

• Improper communication line between PCM and

scan tool.

.

TROUBLESHOOTING HINTS (The most
likely causes for this case:)

• Malfunction of PCM power supply circuit.

• Malfunction of the PCM.

• Open circuit between PCM and data link connec-

tor.

DIAGNOSIS

STEP 1. Check harness connector B-19 at PCM 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 confirm that the

malfunction symptom is eliminated.

AK303231

CONNECTOR: C-29

C-29

AB

AK303153

4 3 2 1

7 6 5

9 8

11 10

14 13 12

18 17 16 15

CONNECTOR: B-19

PCM

AB

AIR CLEANER

HARNESS CONNECTOR:
COMPONENT SIDE

B-19 (B)

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-1018

STEP2. Check for open circuit, short circuit to ground and
harness damage between data link connector C-125
(terminal No. 7) and PCM connector B-19 (terminal No. 15).

NOTE: Check harness after checking intermediate connectors
C-29. If intermediate connector C-29 are damaged, repair or
replace them. Refer to GROUP 00E, Harness Connector
Inspection

P.00E-2

. Then check that the malfunction is elimi-

nated.
Q: Is the harness wire in good condition?

YES : Refer to INSPECTION PROCEDURE 28

− Power

Supply System and Ignition Switch-IG System

P.13B-1096

.

NO : Repair it. Then confirm that the malfunction symptom

is eliminated.

AK303228

1 2 3 4 5 6

12

11

10

1516

14

13

9

7 8

AB

CONNECTOR: C-125

DATA LINK
CONNECTOR

C-125

ACCELERATOR
PEDAL

HARNESS
CONNECTOR:
COMPONENT SIDE

AK303153

4 3 2 1

7 6 5

9 8

11 10

14 13 12

18 17 16 15

CONNECTOR: B-19

PCM

AB

AIR CLEANER

HARNESS CONNECTOR:
COMPONENT SIDE

B-19 (B)

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-1019

INSPECTION PROCEDURE 3: The Malfunction Indicator Lamp (SERVICE ENGINE SOON or Check
Engine Lamp) Does Not Illuminate Right after the Ignition Switch Is Turned to the "ON" Position.

.

COMMENT

• The combination meter causes the malfunction

indicator lamp (SERVICE ENGINE SOON or
Check Engine Lamp) to illuminate for 20 seconds
immediately after the ignition switch is turned to
the "ON" position occurred.

.

TROUBLESHOOTING HINTS (The most
likely causes for this case:)

• Malfunction of the malfunction indicator lamp

(SERVICE ENGINE SOON or Check Engine
Lamp).

• Open or shorted malfunction indicator lamp

(SERVICE ENGINE SOON or Check Engine
Lamp) circuit.

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, 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) Read the DTC.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is DTC set?

YES : Refer to Diagnostic Trouble Code Chart.
NO : Go to step 2.

127 126 125 124 123 122 121

133 132 131 130 129 128

140 139 138 137 136 135 134

146 145 144 143 142 141

153 152 151 150 149 148 147

AK303058

HARNESS CONNECTOR:
COMPONENT SIDE

CONNECTOR: B-23

B-23

PCM

AB

AIR CLEANER