Mitsubishi Lancer Evolution X. Manual — part 277

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-173

DTC P0112: Intake Air Temperature Circuit Low Input (sensor 1)

CIRCUIT OPERATION

• Approximately 5 volts are applied to the intake air

temperature sensor 1 output terminal (terminal
No. 1) from the ECM (terminal No. 89) via the
resistor in the ECM. The ground terminal (termi-
nal No. 4) is grounded with ECM (terminal No.
88).

• The intake air temperature sensor 1 is a negative

temperature coefficient type of resistor. When the
intake air temperature rises, the resistance
decreases.

• The intake air temperature sensor 1 output volt-

age increases when the resistance increases and
decreases when the resistance decreases.

TECHNICAL DESCRIPTION

• The intake air temperature sensor 1 converts the

intake air temperature to a voltage.

• The ECM checks whether this voltage is within a

specified range.

AK704241

71 72 73 74 75 76 77 78 79 80 81 82

83 84 85 86 87 88 89 90 91 92 93 94

95 96 97 98 99

100 101 102 103 104

112 113 114

109

108

107

110 111

115 116

106

105

118

117

3 4

INTAKE AIR TEMPERATURE
SENSOR 1 (INTEGRATED IN
MASS AIRFLOW SENSOR)

ENGINE
CONTROL
MODULE

5 V

INTAKE AIR TEMPERATURE SENSOR 1 CIRCUIT

VIOLET

BLA

CK-BLUE

A-07

(MU805110)

B-10

AK704234

Connector: A-07

Intake air temperature
sensor 1 (integrated in mass
airflow sensor)

A-07 (GR)

AK704235 AB

Connector: B-10

ECM

B-10 (GR)

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

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DESCRIPTIONS OF MONITOR METHODS

Intake air temperature sensor 1 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 Condition

• 2 seconds or more have passed since the engine

starting sequence was completed.

Judgement Criterion

• Intake air temperature sensor 1 output voltage

has continued to be 0.2 volt or lower [correspond-
ing to an intake air temperature of 115° C (239° F)

or higher] for 2 seconds.

Output voltage < 0.2V

Output voltage > 4.6V

End

Malfunction

Good

AK604315

Start

Yes

Continuous

failure for 2secs

Monitoring
conditions

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

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MULTIPORT FUEL INJECTION (MFI)

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FAIL-SAFE AND BACKUP FUNCTION

• Control as if the intake air temperature is 25 ° C.

OBD-II DRIVE CYCLE PATTERN

Refer to Diagnostic Function − OBD-II Drive Cycle −

Pattern 23

P.13A-9

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

• Intake air temperature sensor 1 failed.
• Shorted intake air temperature sensor 1 circuit, or

connector damage.

• ECM failed.

DIAGNOSIS

Required Special Tools:

• MB991958: Scan Tool (M.U.T.-III Sub Assembly)

• MB991824: V.C.I.
• MB991827: USB Cable
• MB991910: Main Harness A

STEP 1. Using scan tool MB991958, check data list item 5:
Intake Air Temperature Sensor 1.

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

5, Intake Air Temperature Sensor 1.

• The intake air temperature and temperature shown with

the scan tool should approximately match.

(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 − How to

Cope with Intermittent Malfunctions

P.00-15

NO : Go to Step 2.

STEP 2. Check harness connector A-07 at the intake air
temperature sensor 1 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 6.

AC608435

Data link connector

MB991827

MB991824

MB991910

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

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STEP 3. Check the intake air temperature sensor 1.
(1) Disconnect the intake air temperature sensor 1 connector

A-07.

(2) Measure the resistance between intake air temperature

sensor 1 side connector terminal No. 1 and No. 4.

• There should be continuity. (0.31 − 17 kΩ)

Q: Is the measured resistance between 0.31 and 17 kΩ?

YES : Go to Step 4.
NO : Replace the mass airflow sensor. Then go to Step 6.

STEP 4. Check for short circuit to ground between intake
air temperature sensor 1 connector A-07 (terminal No. 1)
and ECM connector B-10 (terminal No. 89).
Q: Is the harness wire in good condition?

YES : Go to Step 5.
NO : Repair it. Then go to Step 6.

STEP 5. Check harness connector B-10 at ECM for
damage.
Q: Is the harness connector in good condition?

YES : Replace the ECM. When the ECM is replaced,

P.42B-11

or GROUP 42C, ID Codes

Registration Judgment Table <Vehicles with WCM>

P.42C-9

. Then go to Step 6.

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

Connector Inspection

P.00E-2

. Then go to Step 6.