Mitsubishi Montero (2002-2004). Manual — part 630

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DIAGNOSTIC TROUBLE CODE PROCEDURES

13Ac-217

DTC P0154: Heated Oxygen Sensor Circuit No Activity Detected (bank 2, sensor 1)

.

Heated Oxygen Sensor Circuit No Activity
Detected (bank 2, sensor 1) Circuit

• Refer to, DTC P0150 − Left Bank Heated Oxygen

Sensor (Front) Circuit

P.13Ac-189

.

• Refer to, DTC P0201, P0202, P0203, P0204,

P0205, P0206

− Injector Circuit

P.13Ac-318

.

.

CIRCUIT OPERATION

• Refer to, DTC P0152 − Left Bank Heated Oxygen

Sensor (Front) Circuit

P.13Ac-210

.

• Refer to, DTC P0201, P0202, P0203, P0204,

P0205, P0206

− Injector Circuit

P.13Ac-318

.

.

TECHNICAL DESCRIPTION

• The PCM effects air/fuel ratio feedback control in

accordance with the signals from the left bank
heater oxygen sensor (front).

• If the left bank heated oxygen sensor (front) has

deteriorated, corrections will be made by the
heated oxygen sensor (rear).

• DTC P0154 becomes stored in memory if a fail-

ure is detected in the above air/fuel ratio feed-
back control system.

.

DTC SET CONDITIONS

• Engine coolant temperature is higher than 76°C

(169

° F).

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

• Volumetric efficiency is at between 30 and 80

percent.

• Throttle position sensor output voltage is lower

than 4 volts.

• Except while fuel is being shut off.

• Monitoring time: 30 seconds.

Judgment Criteria

• Left bank heated oxygen sensor (front) output

voltage does not get across 0.5 volt within about
30 seconds.

.

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

• Left bank heated oxygen sensor (front) deterio-

rated.

• Open circuit in left bank heated oxygen sensor

(front) output line.

• Open circuit in left black heated oxygen sensor

(front) ground line.

• Left bank heated oxygen sensor (rear) deterio-

rated.
NOTE: When the left bank heated oxygen sensor
(front) begins to deteriorate, the heated oxygen
sensor output voltage will deviate from the volt-
age when the sensor was new (normally 0.5 volt
at stoichiometric ratio). This deviation will be cor-
rected by the left bank heated oxygen sensor
(rear).
If the left bank heated oxygen sensor (rear)
responds poorly because it has deteriorated, it
will improperly correct the left bank heated oxy-
gen sensor (front). Thus, even when closed loop
control is being effected, the fluctuation of the left
bank heated oxygen sensor (front) output voltage
decreases, without intersecting with 0.5 volt. As a
result, there is a possibility of DTC P0154 becom-
ing registered.

• PCM failed.

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DIAGNOSTIC TROUBLE CODE PROCEDURES

13Ac-218

DIAGNOSIS

Required Special Tools:

• MB991502: Scan Tool (MUT-II)

• MB991316: Test Harness

STEP 1. Using scan tool MB991502, check data list item 59:
Heated Oxygen Sensor Bank 2, Sensor 2 (left rear).

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

59, Heated Oxygen Sensor Bank 2, Sensor 2 (left rear).

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

output voltage should repeat 0 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 : Go to Step 2.
NO : Refer to, DTC P0156

− Heated Oxygen Sensor Circuit

(bank 2, sensor 2)

P.13Ac-235

, DTC P0157

− Heated

Oxygen Sensor Circuit Low Voltage (bank 2, sensor
2)

P.13Ac-250

, DTC P0158-Heated Oxygen Sensor

Circuit High Voltage (bank 2, sensor 2)

P.13Ac-256

,

DTC P0159

− Heated Oxygen Sensor Circuit Slow

Response (bank 2, sensor 2)

P.13Ac-260

.

STEP 2. Check the exhaust leaks.
Q: Are there any abnormalities?

YES : Repair it. Then go to Step 14.
NO : Go to Step 3.

STEP 3. Check the intake system vacuum leak.
Q: Are there any abnormalities?

YES : Go to Step 4.
NO : Repair it. Then go to Step 14.

ACX01539

16-PIN

MB991502

AC

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DIAGNOSTIC TROUBLE CODE PROCEDURES

13Ac-219

STEP 4. Check connector B-26 at the left bank heated
oxygen sensor (front) 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 14.

AK201278

1

2

3

4

CONNECTOR: B-26

B-26(GR)

AB

HARNESS
CONNECTOR:
COMPONENT
SIDE

RIGHT BANK
HEATED OXYGEN
SENSOR (FRONT)

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DIAGNOSTIC TROUBLE CODE PROCEDURES

13Ac-220

STEP 5. 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,
MB991316 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 left 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 terminalNo. 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 6.
NO : Replace the left bank heated oxygen sensor (front).

Then go to Step 14.

STEP 6. Check connector B-44 at injector intermediate
connector for damage.
Q: Is the connector in good condition?

YES : Go to Step 7.
NO : Repair or replace it. Refer to GROUP 00E, Harness

Connector Inspection

P.00E-2

. Then go to Step 14.

AK201278

1

2

3

4

CONNECTOR: B-26

B-26(GR)

AB

HARNESS
CONNECTOR:
COMPONENT
SIDE

RIGHT BANK
HEATED OXYGEN
SENSOR (FRONT)

AKX01625 AB

BLUE

JUMPER
WIRES

BLACK

RED

WHITE

MB991316

AK200949

3

4

7

8

1

2

5

6

B-44(B)

CONNECTOR: B-44

AB

HARNESS
CONNECTOR:
COMPONENT SIDE