Mitsubishi Montero (2004+). Manual - part 175

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-187

• At least 20 seconds have passed since fuel shut 

off control was canceled.

• 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 0.2 
volt.

.

OBD-II DRIVE CYCLE PATTERN
Refer to Diagnostic Function 

− OBD-II Drive Cycle − 

Procedure 6 

− Other Monitor 

P.13A-4

.

.

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

• Right bank heated oxygen sensor (front) failed.

• Short circuit in right bank heated oxygen sensor 

(front) output line.

• Connector damage.

• PCM failed.

DIAGNOSIS

Required Special Tools:

• MB991958: Scan Tool (MUT-III Sub Assembly)

• MB991824: V.C.I.

• MB991827: USB Cable

• MB991911: Main Harness B

• MD998464: Test Harness

STEP 1. Using scan tool MB991958, check data list item 39: 
Heated Oxygen Sensor Bank 1, Sensor 1 (right front).

CAUTION

To prevent damage to scan tool MB991958, always turn the 
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991958.
(1) Connect scan tool MB991958 to the data link connector.
(2) Start the engine and run at idle.
(3) Set scan tool MB991958 to the data reading mode for item 

39, Heated Oxygen Sensor Bank 1, Sensor 1 (right 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.

AK302970

AB

MB991911

MB991824

MB991827

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-188

STEP 2. 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 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 of special tool) and terminal No. 4 (white clip of 
special tool).

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

bank 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 right bank heated 
oxygen sensor (front).

• Be careful the heater is broken when voltage of beyond 

8 volts is applied to the right bank heated oxygen sen-
sor (front) heater.
NOTE: If the sufficiently high temperature [of approximate 
400

°

C(752

°

F) or more] is not reached although the right 

bank heated oxygen sensor (front) 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 terminal No. 1 (red clip of special tool) 
and the terminal No. 3 (blue clip of special tool) of the right 
bank heated oxygen sensor (front) with the positive terminal 
and the negative terminal of 8 volts power supply respec-
tively, then check again.

Q: Is the voltage between 0.6 and 1.0 volt?

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

Then go to Step 5.

AK201274

1

2

3

4

CONNECTOR: B-07

B-07(B)

AB

HARNESS 
CONNECTOR: 
COMPONENT SIDE

RIGHT BANK
HEATED OXYGEN
SENSOR (FRONT)

AKX01624

HEATED
OXYGEN
SENSOR
COMPONENT
SIDE
CONNECTOR

MD998464

WHITE

BLACK

AL

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-189

STEP 3. Check connector B-07 at right 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.

AK201274

1

2

3

4

CONNECTOR: B-07

B-07(B)

AB

HARNESS 
CONNECTOR: 
COMPONENT SIDE

RIGHT BANK
HEATED OXYGEN
SENSOR (FRONT)

AK200947

91

92

93

94

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96

97

98

99

100

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102

103

104

105

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108

109

110

111

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119

120

CONNECTOR: D-135

HARNESS CONNECTOR: 
COMPONENT SIDE

AB

PCM

D-135(GR)

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-190

STEP 4. Check for short circuit to ground between right 
bank heated oxygen sensor (front) connector B-07 
(terminal No. 4) and PCM connector D-135 (terminal No. 
109).
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.

STEP 5. Perform 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-4

.

(2) Check the diagnostic trouble code (DTC).
Q: Is DTC P0131 set?

YES : Repeat the troubleshooting.
NO :  The procedure is complete.

AK201274

1

2

3

4

CONNECTOR: B-07

B-07(B)

AB

HARNESS 
CONNECTOR: 
COMPONENT SIDE

RIGHT BANK
HEATED OXYGEN
SENSOR (FRONT)

AK200947

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92

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103

104

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107

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109

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120

CONNECTOR: D-135

HARNESS CONNECTOR: 
COMPONENT SIDE

AB

PCM

D-135(GR)

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