Mitsubishi Galant 9G. Manual — part 1074

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-596

DTC P0325: Knock Sensor Circuit Malfunction

CAUTION

If DTC P0325 has been set, TCL related DTC
U1120 is also set. After P0325 has been diag-
nosed, don't forget to erase DTC U1120.

WHITE

BLA

CK

BLA

CK

BLA

CK

BLA

CK

AK400913

2

1

B-120

MU802661

KNOCK SENSOR

1

2

POWERTRAIN
CONTROL
MODULE (PCM)

59

Knock Sensor 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

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MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-597

.

CIRCUIT OPERATION

• The knock sensor sends a signal voltage to the

PCM (terminal No. 59).

.

TECHNICAL DESCRIPTION

• The knock sensor converts the vibration of the

cylinder block into a voltage and outputs it. If
there is a malfunction of the knock sensor, the
voltage output will not change.

• The PCM checks whether the voltage output

changes.

.

DTC SET CONDITIONS

Check Conditions

• Engine speed is higher than 2,500 r/min.

• Volumetric efficiency is 40 percent or higher.

Judgment Criteria

• Knock sensor output voltage (knock sensor peak

voltage in each 1/3 turn of the crankshaft) has not
changed more than 0.06 volt in the last consecu-
tive 200 periods.

.

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

• Knock sensor failed.

• Open or shorted knock sensor circuit, or harness

damage, or connector damage.

• PCM failed.

AK303118

AK303118

KNOCK SENSOR

AB

CONNECTOR: B-120

B-120 (GR)

AK303119

CONNECTOR: B-21

PCM

AB

AIR CLEANER

B-21

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

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MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-598

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-120 at the knock
sensor 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 6.

AK303120

1

2

KNOCK SENSOR

AB

CONNECTOR: B-120

B-120 (GR)

HARNESS
CONNECTOR:
COMPONENT SIDE

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

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MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-599

STEP 2. Check the continuity at knock sensor harness
side connector B-120.
(1) Disconnect the connector B-120 and measure at the

harness side.

(2) Check for the continuity between terminal No. 2 and

ground.

• Should be less than 2 ohms.

Q: Does continuity exist?

YES : Go to Step 3.
NO : Repair an open circuit or harness damage between

knock sensor connector B-120 (terminal No. 2) and
ground. Then go to Step 6.

AK303120

1

2

KNOCK SENSOR

AB

CONNECTOR: B-120

B-120 (GR)

HARNESS
CONNECTOR:
COMPONENT SIDE

AK303121 AB

B-120 HARNESS
CONNECTOR:
COMPONENT SIDE

1

2