Mitsubishi Montero Sport (2004+). Manual - part 181

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-137

DTC P0121: Throttle Position Sensor Circuit Range/Performance Problem

5V

GREEN-

YELL

OW

BL

ACK

GREEN-

WHITE

GREEN-

WHITE

BL

ACK

AK000443

Throttle Position Sensor (TPS) Circuit

POWERTRAIN CONTROL MODULE (PCM)

71

76

77

72 73 74

75

79 80

78

81

87 88

89

91

90

92

97

98

82

93

83

94

84 85

95

86

96

C-91
(MU803782)

1 2 3 4

A-41
(MU802724)

THROTTLE POSITION SENSOR

13

12

78

57

3

1

4

C-90

46

47

41

42 43

48 49 50 51 52 53 54 55 56 57

46

45

44

58

59

60 61 62 63

64 65 66

C-90
(MU803781)

1

10

2 3 4 5 6 7 8 9

11

12 13 14 15 16 17 18 19 20 21 22

23 24 25 26 27 28 29 30 31 32 33

C-71

AUTO-CRUISE CONTROL SYSTEM

C-91

JOINT
CONNEC-
TOR (4)

AK000363

AK104024

CONNECTOR: A-41

AB

THROTTLE
POSITION
SENSOR

A-41(B)

AK103738AE

CONNECTORS: C-90, C-91

PCM

C-91(GR)

C-90(GR)

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-138

.

CIRCUIT OPERATION

• A 5-volt power supply is applied on the TPS 

power terminal (terminal No. 4) from the PCM 
(terminal No. 46). 
The ground terminal (terminal No. 1) is grounded 
with PCM (terminal No. 57).

• When the throttle valve shaft is turned from the 

idle position to the fully opened position, the 
resistor between the TPS output terminal (termi-
nal No. 3) and ground terminal will increase 
according to the rotation. 

.

TECHNICAL DESCRIPTION

• The TPS outputs voltage which corresponds to 

the throttle valve opening angle.

• The PCM checks whether the voltage is within a 

specified range. 

.

DESCRIPTIONS OF MONITOR METHODS
Compare load value with throttle position sensor out-

put voltage.

.

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)

• Not applicable

Sensor (The sensor below is determined to be 

normal)

• Volume airflow sensor

.

AK103912AB

CONNECTOR: C-71

C-71

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-139

DTC SET CONDITIONS <Range/Performance problem-low input>

Logic Flow Chart

.

Check Conditions

• 2 seconds or more have passed since the staring 

sequence was completed.

• Engine speed is higher than 2,000 r/min.

• Volumetric efficiency is higher than 60 percent.

Judgement Criteria

• TPS output voltage has continued to be 0.8 volt 

or lower for 2 seconds.

.

START

ENGINE SPEED > 2000r/min

LOAD VALUE > 60%

END

NO

NO

NO

NO

YES

YES

YES

YES

MALFUNCTION

GOOD

OUTPUT VOLTAGE

< 0.8V

MONITORING
CONDITIONS

CONTINUOUS

FAILURE FOR 2 secs

AK304165

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-140

DTC SET CONDITIONS <Range/Performance problem-high input>

Logic Flow Chart

Check Conditions

• 2 seconds or more have passed since the staring 

sequence was completed.

• Engine speed is lower than 3,000 r/min.

• Volumetric efficiency is lower than 30 percent.

Judgement Criteria

• TPS output voltage has continued to be 4.6 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:)

• TPS failed or incorrectly adjusted.

• Open TPS circuit, harness damage or connector 

damage.

• PCM failed.

START

ENGINE SPEED < 3000r/min

LOAD VALUE < 30%

END

NO

NO

NO

NO

YES

YES

YES

YES

MALFUNCTION

GOOD

MONITORING
CONDITIONS

CONTINUOUS

FAILURE FOR 2 secs

OUTPUT VOLTAGE

> 4.6V

AK304166