Mitsubishi Montero (2002-2004). Manual - part 627

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DIAGNOSTIC TROUBLE CODE PROCEDURES

13Ac-205

CIRCUIT OPERATION

• A voltage corresponding to the oxygen concen-

tration in the exhaust gas is sent to the PCM (ter-
minal No. 108) from the output terminal (terminal
No. 4) of the left bank heated oxygen sensor
(front).

• Terminal No. 2 of the left bank heated oxygen

sensor (front) is grounded with PCM (terminal
No. 96).

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 PCM.

• When the left bank heated oxygen sensor (front)

begins to deteriorate, the heated oxygen sensor
signal response deteriorates also.

• The PCM 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 PCM also checks for an
open circuit in the left bank heated oxygen sensor
(front) output line.

DTC SET CONDITIONS

Check Conditions

• 3 minutes or more have passed since the starting

sequence was completed.

• Left bank heated oxygen sensor (front) signal

voltage has continued to be 0.2 volt or lower.

• Engine coolant temperature is higher than 76°C

(169

°F).

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

• Volumetric efficiency is higher than 25 percent.

• Volume airflow sensor output frequency is 100 Hz

or more.

• At least 20 seconds have passed since fuel shut

off control was canceled.

• After the ignition switch is turned "ON" position,

the changes in the output voltage of the left bank
heated oxygen sensor (front) is lower than 0.078
volt.

• Monitoring time: 10 seconds.

Judgement Criteria

• Making the air/fuel ratio 15 percent for 10 sec-

onds richer does not result in raising the heated
oxygen sensor (front) output voltage beyond 0.15
volt.

• The PCM monitors for this condition once during

the drive cycle.

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

• Left bank heated oxygen sensor (front) failed.

• Short circuit in left bank heated oxygen sensor

(front) output line.

• PCM failed.

AK201049

CONNECTOR: D-116

D-116

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DIAGNOSTIC TROUBLE CODE PROCEDURES

13Ac-206

DIAGNOSIS

Required Special Tools:

• MB991502: Scan Tool (MUT-II)

• MD998464: Test Harness

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 con-
necting 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).

• Warm up the engine. When the engine is revved, the

output voltage should measure 0.6 to 1.0 volt.

• Warm up the engine. When the engine is idling, the out-

put 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.

AC003081 AB

16 PIN

MB991502

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DIAGNOSTIC TROUBLE CODE PROCEDURES

13Ac-207

STEP 2. Check the left bank heated oxygen sensor (front).
(1) Disconnect the left bank heated oxygen sensor (front)

connector B-26 and connect test harness special tool,
MD998464, to the connector on the left bank heated oxygen
sensor (front) side.

(2) Warm up the engine until engine coolant 80

°C (176°F) or

higher.

CAUTION

Be very careful when connecting the jumper wires; incor-
rect connection can damage the right bank heated oxygen
sensor (front).

(3) Use the jumper wires to connect terminal No. 1 (red clip) to

the positive battery terminal and terminal No. 3 (blue clip) to
the negative battery terminal.

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

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

(5) While repeatedly revving the engine, measure the left bank

heated oxygen sensor (front) output voltage.

Standard value: 0.6

− 1.0 volt

Q: Is the voltage between 0.6 and 1.0 volt?

YES : Go to Step 3.
NO : Replace the left bank heated oxygen sensor (front).

Then go to Step 5.

AK201278

CONNECTOR: B-26

B-26(GR)

HARNESS
CONNECTOR:
COMPONENT
SIDE

RIGHT BANK
HEATED OXYGEN
SENSOR (FRONT)

AKX01625AC

BLUE

RED

BLACK

JUMPER
WIRES

WHITE

MD998464

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DIAGNOSTIC TROUBLE CODE PROCEDURES

13Ac-208

STEP 3. Check connector B-26 at left bank heated oxygen
sensor (front) and connector D-135 at PCM for damage.
Q: Is the 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.

AK201278

CONNECTOR: B-26

B-26(GR)

HARNESS
CONNECTOR:
COMPONENT
SIDE

RIGHT BANK
HEATED OXYGEN
SENSOR (FRONT)

AK200947

100

101

102

103

104

105

106

107

108

109

110

111

112

113

114

115

116

117

118

119

120

CONNECTOR: D-135

HARNESS CONNECTOR:
COMPONENT SIDE

PCM

D-135(GR)

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