Mitsubishi Montero (2004+). Manual - part 201

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-291

DTC P0152: Heated Oxygen Sensor Circuit High Voltage (bank 2, sensor 1)

BL

ACK

BL

ACK

BL

ACK

TO PCM

FROM MFI RELAY

WHITE

AK201135

96

108

4

3

1

LEFT BANK
HEATED OXYGEN
SENSOR (FRONT)

POWERTRAIN CONTROL
MODULE (PCM)

11

9

7

2

4

3

1 2

B-26

MU802665

1

12

23 24 25 26

2

13

3

14

4

15

5

16

6

17

7

18

8

19

9

20 21 22

27 28 29 30 31 32 33

10 11

D-116

1
5

7 8

3 4
9 10

2
6

D-14

MU801335

Left Bank Heated Oxygen Sensor (front) Circuit

9192

939495

96979899

100

105

113114

115116117

118119120

106

107108109

110111112

101102103

104

D-135

(MU803805)

AK201277

CONNECTOR: B-26

B-26(GR)

AD

LEFT BANK
HEATED OXYGEN
SENSOR (FRONT)

AK201038AF

CONNECTOR: D-135

PCM

D-135(GR)

AK201049

D-14

AB

CONNECTOR: D-14

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-292

.

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.

.

DESCRIPTIONS OF MONITOR METHODS
Left bank heated oxygen sensor (front) output volt-

age is over specified range.

.

MONITOR EXECUTION
Continuous

.

MONITOR EXECUTION CONDITIONS (Other 
monitor and Sensor)

Other Monitor (There is no temporary DTC stored 

in memory for the item monitored below)

• Heated oxygen sensor heater (front) monitor

• Misfire monitor

• Fuel system monitor

Sensor (The sensor below is determined to be 

normal)

• Volume airflow sensor

• Engine coolant temperature sensor

• Intake air temperature sensor

• Barometric pressure sensor

• Throttle position sensor

• Accelerator pedal position sensor

.

AK201049

CONNECTOR: D-116

D-116

AC

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-293

DTC SET CONDITIONS

Logic Flow Chart

.

DTC SET CONDITIONS

Check Conditions

• 2 seconds or more have passed since the engine 

starting sequence was completed.

Judgment Criteria

• Left bank heated oxygen sensor (front) output 

voltage has continued to be 1.2 volts or higher for 
2 seconds.

.

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: )

• Short circuit in left 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

START

END

NO

NO

YES

YES

MALFUNCTION

GOOD

2secs HAVE PASSED?

OUTPUT VOLTAGE > 1.2V

NO

YES

MONITORING

CONDITIONS

AK302931

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-294

STEP 1. 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 2.
NO :  Repair or replace it. Refer to GROUP 00E, Harness 

Connector Inspection 

P.00E-2

. Then go to Step 3.

AK201278

1

2

3

4

CONNECTOR: B-26

B-26(GR)

AC

HARNESS 
CONNECTOR: 
COMPONENT 
SIDE

LEFT BANK
HEATED OXYGEN
SENSOR (FRONT)

AK200947

91

92

93

94

95

96

97

98

99

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

AB

PCM

D-135(GR)