Mitsubishi Montero (2002-2004). Manual — part 598

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DIAGNOSTIC TROUBLE CODE PROCEDURES

13Ac-89

P0123 Throttle Position Sensor (Main) Circuit high Input

.

CIRCUIT OPERATION

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

(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
resister between the TPS (main) output terminal
(terminal No. 1) and ground terminal will increase
according to the rotation.

.

TECHNICAL DESCRIPTION

• The TPS (main) outputs voltage which corre-

sponds to the throttle valve opening angle.

AK201130

RED

WHITE

BLA

CK

B-05

5 V

106

2

THROTTLE
POSITION
SENSOR
(MAIN)

POWERTRAIN CONTROL MODULE (PCM)

115

105

1

4

Throttle Position Sensor (Main) Circuit

9192

939495

96979899

100

105

113114

115116117

118119120

106

107108109

110111112

101102103

104

D-135

(MU803805)

6

1 2 3 4 5

AK201173

THROTTLE
POSITION
SENSOR

AB

B-05(B)

CONNECTOR: B-05

AK201038AF

CONNECTOR: D-135

PCM

D-135(GR)

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DIAGNOSTIC TROUBLE CODE PROCEDURES

13Ac-90

• The PCM checks whether the voltage is within a

specified range.

.

DTC SET CONDITIONS

Check Conditions

• Ignition switch "ON" position.

Judgement Criteria

• TPS (main) output voltage should be 4.8 volts or

more for 0.5 seconds.

.

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

• TPS failed or maladjusted.

• Open or shorted TPS (main) circuit, or loose con-

nector.

• PCM failed.

DIAGNOSIS

Required Special Tool:

• MB991502: Scan Tool (MUT-II)

STEP 1. Using scan tool MB991502, check data list item 79:
Throttle Position Sensor (main).

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) 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 (MB991348) to connect only

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

(6) Set scan tool MB991502 to the data reading mode for item

79, Throttle Position Sensor (main).

• Output voltage should be between 0.2 and 0.8 volts

when the throttle valve is fully closed with your finger.

• Output voltage should be between 3.8 and 4.9 volts

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 connector B-05 at throttle position sensor
for damage.
Q: Is the 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 9.

ACX01539

16-PIN

MB991502

AC

AK201174

1

6 5 4 3 2

B-05(B)

CONNECTOR: B-05

HARNESS
CONNECTOR:
COMPONENT SIDE

AB

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DIAGNOSTIC TROUBLE CODE PROCEDURES

13Ac-91

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: Is the continuity normal?

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

STEP 4. Check connector D-135 at PCM 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 9.

AK201174

1

6 5 4 3 2

B-05(B)

CONNECTOR: B-05

HARNESS
CONNECTOR:
COMPONENT SIDE

AB

AK201446

1

6 5 4 3 2

AB

B-05 HARNESS
CONNECTOR:
COMPONENT SIDE

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)

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DIAGNOSTIC TROUBLE CODE PROCEDURES

13Ac-92

STEP 5. Check for open circuit and harness damage
between throttle position sensor connector B-05 (terminal
No. 4) and PCM connector D-135 (terminal No. 105).
Q: Is the harness wire in good condition?

YES : Go to Step 6.
NO : Repair it. Then go to Step 9.

AK201174

1

6 5 4 3 2

B-05(B)

CONNECTOR: B-05

HARNESS
CONNECTOR:
COMPONENT SIDE

AB

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)