Mitsubishi Eclipse / Eclipse Spyder (2000-2002). Service and repair manual — part 239

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L ENGINE>

13B-155

CIRCUIT OPERATION

•

A voltage corresponding to the oxygen
concentration in the exhaust gas is sent to the
ECM (terminal 71) <M/T> or PCM (terminal 71)
<A/T> from the output terminal (terminal 4) of the
left bank heated oxygen sensor (front).

•

Terminal 2 of the left bank heated oxygen sensor
(front) is grounded with ECM (terminal 49) <M/T>
or PCM (terminal 57) <A/T>.

TECHNICAL DESCRIPTION

•

The left bank heated oxygen sensor (front)
detects the concentration of oxygen in the
exhaust gas; it converts that data to voltage, and
sends it to the ECM <M/T> or PCM <A/T>.

•

When the left bank heated oxygen sensor (front)
begins to deteriorate, the heated oxygen sensor
signal response deteriorates also.

•

The ECM <M/T> or PCM <A/T> varies the air/fuel
mixture to make it leaner and richer, and checks
the response speed of the left bank heated
oxygen sensor (front). In addition, the ECM <M/
T> or PCM <A/T> also checks for an open circuit
in the left bank heated oxygen sensor (front)
output line.

DTC SET CONDITIONS

Check Conditions

•

Left bank heated oxygen sensor (front) signal
voltage has continued to be 0.2 volt or lower for
three minutes or more after engine starting
sequence was completed.

•

Engine coolant temperature is higher than 82

°

C

(180

°

F).

•

Engine speed is higher than 1,200 r/min.

•

Volumetric efficiency is higher than 25 percent.

•

Monitoring time: 7 seconds.

Judgment Criteria

•

Input voltage supplied to the ECM <M/T> or PCM
<A/T> interface circuit is higher than 4.5 volts
when 5 volts is applied to the left bank heated
oxygen sensor (front) output line via a resistor.

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

•

Left bank heated oxygen sensor (front)
deteriorated.

•

Open circuit in left bank heated oxygen sensor
(front) output line.

•

Open circuit in left bank heated oxygen sensor
(front) ground line.

•

ECM failed. <M/T>

•

PCM failed. <A/T>

DIAGNOSIS

Required Special Tools
MB991502: Scan Tool (MUT-II)
MD998464: Test Harness

ACX02489AC

CONNECTOR : B-24

LEFT BANK
HEATED OXYGEN
SENSOR
(FRONT)

AK000225

CONNECTORS : C-58, C-62<M/T>,
C-55, C-59<A/T>

C-55

C-58

PCM<A/T>

ECM<M/T>

AK

C-59

C-62

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L ENGINE>

13B-156

STEP 1. Using scan tool MB991502, check data list item 11:
Heated Oxygen Sensor Bank 2, Sensor 1 (left front).

CAUTION

To prevent damage to scan tool MB991502, always turn the
ignition switch to the "LOCK" (OFF) position before
connecting or disconnecting scan tool MB991502.
(1) Connect scan tool MB991502 to the data link connector.
(2) Start the engine and run at idle.
(3) Set scan tool MB991502 to the data reading mode for item

11, Heated Oxygen Sensor Bank 2, Sensor 1 (left front).

•

Warming up the engine. When the engine is revved, the
output voltage should be 0.6 to 1.0 volt.

•

Warming up the engine. When the engine is idling, the
output voltage should repeat 0.4 volt and 0.6 to 1.0 volt
alternately.

(4) Turn the ignition switch to the "LOCK" (OFF) position.

Q: Is the sensor operating properly?

YES : It can be assumed that this malfunction is intermittent.

Refer to GROUP 00, How to Use Troubleshooting/
Inspection Service Points (

P.00-6

).

NO : Go to Step 2.

STEP 2. Check the sensor output voltage at left bank
heated oxygen sensor (front) connector B-24 by
backprobing.
(1) Do not disconnect the connector B-24.
(2) Start the engine and run at idle.
(3) Measure the voltage between terminal 4 and ground by

backprobing.

•

Warming up the engine. When the engine is 2,500 r/min,
the output voltage should repeat 0 to 0.8 volt alternately.

(4) Turn the ignition switch to the "LOCK" (OFF) position.

Q: Is the voltage normal?

YES : Go to Step 3.
NO : Go to Step 7.

AKX01177

16 PIN

MB991502

AB

AKX01541AD

1 2
3 4

B-24 CONNECTOR
HARNESS
SIDE VIEW

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L ENGINE>

13B-157

STEP 3. Check the sensor output voltage at ECM
connector C-62 <M/T> or PCM connector C-59 <A/T> by
backprobing.
(1) Do not disconnect the connector C-62 <M/T> or C-59 <A/

T>.

(2) Start the engine and run at idle.
(3) Measure the voltage between terminal 71 and ground by

backprobing.

•

Warming up the engine. When the engine is 2,500 r/min,
the output voltage should repeat 0 to 0.8 volt alternately.

(4) Turn the ignition switch to the "LOCK" (OFF) position.

Q: Is the voltage normal?

YES : Go to Step 4.
NO : Go to Step 6.

STEP 4. Check connector B-24 at left bank heated oxygen
sensor (front) and connector C-62 at ECM <M/T> or
connector C-59 at PCM <A/T> for damage.
Q: Is the connector in good condition?

YES : Go to Step 5.
NO : Repair or replace it. Refer to GROUP 00E, Harness

Connector Inspection (

P.00E-2

). Then go to Step 15.

AK000244

71 72

73 74

78

80 81

79

82 83 84 85 86 87 88 89

75 76

91 92 93

94 95

96

98

99

97

AK000244AC

<M/T>

C-62 CONNECTOR
HARNESS SIDE VIEW

77

90

100

AKX01539

AKX01539

7172 73 74

75 76 77

78 79 80 81 82 83 84 85 86 87 88 89
90 91

92 93 94

95 96

97 98

C-59 CONNECTOR
HARNESS SIDE VIEW

AF

<A/T>

AK000212AB

AK000212

CONNECTOR : B-24

AK000225

CONNECTOR : C-62<M/T>, C-59<A/T>

C-59

C-62

PCM<A/T>

ECM<M/T>

AL

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L ENGINE>

13B-158

STEP 5. Using scan tool MB991502, check data list item 11:
Heated Oxygen Sensor Bank 2, Sensor 1 (left front).

CAUTION

To prevent damage to scan tool MB991502, always turn the
ignition switch to the "LOCK" (OFF) position before
connecting or disconnecting scan tool MB991502.
(1) Connect scan tool MB991502 to the data link connector.
(2) Start the engine and run at idle.
(3) Set scan tool MB991502 to the data reading mode for item

11, Heated Oxygen Sensor Bank 2, Sensor 1 (left front).

•

Warming up the engine. When the engine is revved, the
output voltage should be 0.6 to 1.0 volt.

•

Warming up the engine. When the engine is idling, the
output voltage should repeat 0.4 volt and 0.6 to 1.0 volt
alternately.

(4) Turn the ignition switch to the "LOCK" (OFF) position.

Q: Is the sensor operating properly?

YES : It can be assumed that this malfunction is intermittent.

Refer to GROUP 00, How to Use Troubleshooting/
Inspection Service Points (

P.00-6

).

NO : Replace the ECM or PCM. Then go to Step 15.

STEP 6. Check connector B-24 at left bank heated oxygen
sensor (front) and connector C-62 at ECM <M/T> or
connector C-59 at PCM <A/T> for damage.
Q: Is the connector in good condition?

YES : Repair harness wire between left bank heated oxygen

sensor (front) connector B-24 terminal 4 and ECM
connector C-62 terminal 71 <M/T> or PCM connector
C-59 terminal 71 <A/T> because of open circuit or
harness damage. Then go to Step 15.

NO : Repair or replace it. Refer to GROUP 00E, Harness

Connector Inspection (

P.00E-2

). Then go to Step 15.

AKX01177

16 PIN

MB991502

AB

AK000212AB

AK000212

CONNECTOR : B-24

AK000225

CONNECTOR : C-62<M/T>, C-59<A/T>

C-59

C-62

PCM<A/T>

ECM<M/T>

AL