Mitsubishi Galant (2004+). Manual — part 890

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L ENGINE>

13A-377

STEP 2. Check the cylinder 2, 3 heated oxygen sensor
(rear).

(1) Disconnect the cylinder 2, 3 heated oxygen sensor (rear)

connector B-35 and connect test harness special tool
MD998464 to the connector on the cylinder 2, 3 heated
oxygen sensor (rear) side.

(2) Warm up the engine until engine coolant temperature

reaches 80

°C (176°F) or higher.

(3) Perform a racing for 5 minutes or more with the engine

speed of 4,500 r/min.

(4) Connect a digital voltage meter between terminal No. 2

(black clip) and terminal No. 4 (white clip).

(5) While repeatedly revving the engine, measure the cylinder

2, 3 heated oxygen sensor (front) output voltage.

Standard value: 0.6

− 1.0 volt

CAUTION

• Be very careful when connecting the jumper wire;

incorrect connection can damage the heated oxygen
sensor (rear).

• Be careful the heater is broken when voltage of beyond

12 volts is applied to the heated oxygen sensor (rear)
heater.
NOTE: If the sufficiently high temperature [of approximate
400

°

C (752

°

F) or more] is not reached although the heated

oxygen sensor (rear) is normal, the output voltage would be
possibly low although the rich air/fuel ratio. Therefore, if the
output voltage is low, use a jumper wire to connect the ter-
minal No. 1 (red clip) and the terminal No. 3 (blue clip) of
the heated oxygen sensor (rear) with the positive terminal
and the negative terminal of 12 volts power supply respec-
tively, then check again.

Q: Is the measured voltage between 0.6 and 1.0 volt?

YES : Go to Step 3.
NO : Replace the cylinder 2, 3 heated oxygen sensor

(rear). Then go to Step 5.

AK303835

1

2

3

4

AB

CONNECTOR: B-35

B-35 (B)

CYLINDER 2, 3
HEATED OXYGEN
SENSOR (REAR)

HARNESS
CONNECTOR:
COMPONENT SIDE

AKX01624

HEATED
OXYGEN
SENSOR
COMPONENT
SIDE
CONNECTOR

MD998464

WHITE

BLACK

AL

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L ENGINE>

13A-378

STEP 3. Check harness connector B-35 at cylinder 2, 3
heated oxygen sensor (rear) and harness connector B-22
at PCM for damage.

Q: Is the harness connector in good condition?

YES : Go to Step 4.
NO : Repair or replace it. Refer to GROUP 00E, Harness

Connector Inspection

P.00E-2

. Then go to Step 5.

AK303835

1

2

3

4

AB

CONNECTOR: B-35

B-35 (B)

CYLINDER 2, 3
HEATED OXYGEN
SENSOR (REAR)

HARNESS
CONNECTOR:
COMPONENT SIDE

AK303016

104

96

94

95

93 92 91

99 98 97

103 102 101 100

108 107 106 105

113 112 111 110 109

CONNECTOR: B-22

B-22 (B)

PCM

AB

HARNESS CONNECTOR:
COMPONENT SIDE

AIR CLEANER

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L ENGINE>

13A-379

STEP 4. Check for short circuit to ground between cylinder
2, 3 heated oxygen sensor (rear) connector B-35 (terminal
No. 4) and PCM connector B-22 (terminal No. 96).

Q: Is the harness wire in good condition?

YES : Replace the PCM. Then go to Step 5.
NO : Repair it. Then go to Step 5.

AK303835

1

2

3

4

AB

CONNECTOR: B-35

B-35 (B)

CYLINDER 2, 3
HEATED OXYGEN
SENSOR (REAR)

HARNESS
CONNECTOR:
COMPONENT SIDE

AK303016

104

96

94

95

93 92 91

99 98 97

103 102 101 100

108 107 106 105

113 112 111 110 109

CONNECTOR: B-22

B-22 (B)

PCM

AB

HARNESS CONNECTOR:
COMPONENT SIDE

AIR CLEANER

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L ENGINE>

13A-380

STEP 5. Test the OBD-II drive cycle.

(1) Carry out a test drive with the drive cycle pattern. Refer to

Diagnostic Function

− OBD-II Drive Cycle − Procedure 6 −

Other Monitor

P.13A-5

.

(2) Check the diagnostic trouble code (DTC).
Q: Is DTC P0157 set?

YES : Retry the troubleshooting.
NO : The inspection is complete.

DTC P0158: Cylinder 2, 3 Heated Oxygen Sensor Circuit High Voltage (sensor 2)

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

100

99

92

91

93 94 95

96 97 98

101 102 103 104

105 106 107 108

109 110 111 112 113

AK303833

1

2

3

4

GREEN

BLUE

BLA

CK

BLA

CK

TO PCM

FROM MFI RELAY

69

96

2

4

3

1

B-22

CYLINDER 2, 3
HEATED OXYGEN
SENSOR (REAR)

POWERTRAIN CONTROL
MODULE (PCM)

B-35

MU802605

Cylinder 2, 3 Heated Oxygen Sensor (rear) Circuit

B-21