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Mitsubishi Montero (2004+). Manual - part 165

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-147

DTC P0123: Throttle Position Sensor (Main) Circuit high Input

CIRCUIT OPERATION

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

position sensor (main) power terminal (terminal
No. 2) from the PCM (terminal No. 106).
The ground terminal (terminal No. 4) is grounded
with PCM (terminal No. 105).

• When the throttle valve shaft is turned from the

idle position to the fully opened position, the
resistance between the throttle position sensor
(main) output terminal (terminal No. 1) and
ground terminal (terminal No. 4) will increase
according to the rotation.

AK201130

RED

WHITE

BLA

B-05

5 V

106

THROTTLE
POSITION
SENSOR
(MAIN)

POWERTRAIN CONTROL MODULE (PCM)

115

105

Throttle Position Sensor (Main) Circuit

9192

939495

96979899

100

105

113114

115116117

118119120

106

107108109

110111112

101102103

104

D-135

(MU803805)

1 2 3 4 5

AK201173

THROTTLE
POSITION
SENSOR

B-05(B)

CONNECTOR: B-05

AK201038

CONNECTOR: D-132

PCM

D-132(GR)

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

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MULTIPORT FUEL INJECTION (MFI)

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TECHNICAL DESCRIPTION

• The throttle position sensor (main) outputs volt-

age which corresponds to the throttle valve open-
ing angle.

• The PCM checks whether the voltage is within a

specified range.

DESCRIPTIONS OF MONITOR METHODS
Throttle position sensor (main) output voltage is out

of 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)

• Not applicable

Sensor (The sensor below is determined to be

normal)

• Not applicable

DTC SET CONDITIONS

Logic Flow Chart

Check Conditions

• Ignition switch "ON" position.

Judgement Criteria

• Throttle position sensor (main) output voltage

should be 4.8 volts or more for 0.5 second.

START

YES

CONTINUOUS

FAILURE FOR 0.5sec

MALFUNCTION

END

GOOD

OUTPUT VOLTAGE

< =0.35V

OUTPUT VOLTAGE > =4.8V

AK302926

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-149

OBD-II DRIVE CYCLE PATTERN
None.

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

• Throttle position sensor failed.

• Open throttle position sensor (main) circuit, har-

ness damage, or 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

• MB991658: Test Harness Set

STEP 1. Using scan tool MB991958, check data list item 79:
Throttle Position Sensor (main).

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) Turn the ignition switch to the "ON" position.
(3) Detach the intake air hose at the throttle body.
(4) Disconnect the connector of the throttle position sensor.
(5) Use test harness special tool (MB991658) to connect only

terminals No. 1, No. 2, No. 3, and No. 4.

(6) Set scan tool MB991958 to the data reading mode for item

79, Throttle Position Sensor (main).

• Output voltage should be between 0.3 and 0.7 volt when

the throttle valve is fully closed with your finger.

• Output voltage should be 4.0 volts or more when the

throttle valve is fully open with your finger.

(7) 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.

STEP 2. Check harness connector B-05 at throttle position
sensor for damage.
Q: Is the harness connector in good condition?

YES : Go to Step 3.
NO : Repair or replace it. Refer to GROUP 00E, Harness

Connector Inspection

P.00E-2

. Then go to Step 8.

AK302970

MB991911

MB991824

MB991827

AK201174

6 5 4 3 2

B-05(B)

CONNECTOR: B-05

HARNESS
CONNECTOR:
COMPONENT SIDE

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

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MULTIPORT FUEL INJECTION (MFI)

13A-150

STEP 3. Check the continuity at throttle position sensor
harness side connector B-05.
(1) Disconnect the connector B-05 and measure at the harness

side.

(2) Measure the continuity between terminal No. 4 and ground

• Should be less than 2 ohms.

Q: Dose continuity exist?

YES : Go to Step 7.
NO : Go to Step 4.

STEP 4. Check harness connector D-135 at PCM for
damage.
Q: Is the harness 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 8.

AK201174

6 5 4 3 2

B-05(B)

CONNECTOR: B-05

HARNESS
CONNECTOR:
COMPONENT SIDE

AK201446

6 5 4 3 2

B-05 HARNESS
CONNECTOR:
COMPONENT SIDE

AK200947

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

PCM

D-135(GR)

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