Mitsubishi Montero (2002-2004). Manual - part 609

TSB Revision

DIAGNOSTIC TROUBLE CODE PROCEDURES

13Ac-133

DTC P0134: Heated Oxygen Sensor Circuit No Activity Detected (bank 1, sensor 1)

.

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

• Refer to, DTC P0130 − Right Bank Heated Oxy-

gen Sensor (Front) Circuit 

P.13Ac-105

.

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

P0205, P0206 

− Injector Circuit 

P.13Ac-318

.

.

CIRCUIT OPERATION

• Refer to, DTC P0132-Right Bank Heated Oxygen 

Sensor (Front) Circuit 

P.13Ac-126

.

• 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 right bank 
heater oxygen sensor (front).

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

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

• DTC P0134 becomes stored in memory if a fail-

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

.

DTC SET CONDITIONS

Check Conditions

• 30 seconds or more have passed since the start-

ing sequence was completed.

• 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

• Right 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: )

• Right bank heated oxygen sensor (front) deterio-

rated.

• Open circuit in right bank heated oxygen sensor 

(front) output line.

• Open circuit in right black heated oxygen sensor 

(front) ground line.

• Right bank heated oxygen sensor (rear) deterio-

rated.
NOTE: When the right bank heated oxygen sen-
sor (front) begins to deteriorate, the heated oxy-
gen sensor output voltage will deviate from the 
voltage when the sensor was new (normally 0.5 
volt at stoichiometric ratio). This deviation will be 
corrected by the right bank heated oxygen sensor 
(rear).
If the right bank heated oxygen sensor (rear) 
responds poorly because it has deteriorated, it 
will improperly correct the right bank heated oxy-
gen sensor (front). Thus, even when closed loop 
control is being effected, the fluctuation of the 
right bank heated oxygen sensor (front) output 
voltage decreases, without intersecting with 0.5 
volt. As a result, there is a possibility of DTC 
P0134 becoming registered.

• PCM failed.

TSB Revision

DIAGNOSTIC TROUBLE CODE PROCEDURES

13Ac-134

DIAGNOSIS

Required Special Tools:

• MB991502: Scan Tool (MUT-II)

• MD998464: Test Harness

STEP 1. Using scan tool MB991502, check data list item 69: 
Heated Oxygen Sensor Bank 1, Sensor 2 (right 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 

69, Heated Oxygen Sensor Bank 1, Sensor 2 (right 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 P0136 

− Heated Oxygen Sensor Circuit 

(bank 1, sensor 2) DTC 

P.13Ac-151

,  P0137 

− Heated 

Oxygen Sensor Circuit Low Voltage (bank 1, sensor 
2) 

P.13Ac-166

, DTC P0138 

− Heated Oxygen Sensor 

Circuit High Voltage (bank 1, sensor 2) 

P.13Ac-172

, 

DTC P0139 

− Heated Oxygen Sensor Circuit Slow 

Response (bank 1, sensor 2) 

P.13Ac-176

. 

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

YES : Repair it. Then go to Step 13.
NO :  Go to Step 3.

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

YES : Repair it. Then go to Step 13.
NO :  Go to Step 4.

ACX01539

16-PIN

MB991502

AC

TSB Revision

DIAGNOSTIC TROUBLE CODE PROCEDURES

13Ac-135

STEP 4. Check connector B-07 at the right 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 13.

AK201274

1

2

3

4

CONNECTOR: B-07

B-07(B)

AB

HARNESS 
CONNECTOR: 
COMPONENT SIDE

RIGHT BANK
HEATED OXYGEN
SENSOR (FRONT)

TSB Revision

DIAGNOSTIC TROUBLE CODE PROCEDURES

13Ac-136

STEP 5. Check the right bank heated oxygen sensor 
(front).
(1) Disconnect the right bank heated oxygen sensor (front) 

connector B-07 and connect test harness special tool, 
MD998464 to the connector on the right 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 right 

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 right bank heated oxygen sensor (front). 

Then go to Step 13.

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 13.

AK201274

1

2

3

4

CONNECTOR: B-07

B-07(B)

AB

HARNESS 
CONNECTOR: 
COMPONENT SIDE

RIGHT BANK
HEATED OXYGEN
SENSOR (FRONT)

AKX01625AC

BLUE

RED

BLACK

JUMPER
WIRES

WHITE

MD998464

AK200949

3

4

7

8

1

2

5

6

B-44(B)

CONNECTOR: B-44

AB

HARNESS 
CONNECTOR: 
COMPONENT SIDE