Mitsubishi 380. Manual - part 496

MULTIPOINT FUEL INJECTION (MPI) DIAGNOSIS

MULTIPOINT FUEL INJECTION (MPI)

13A-76

DTC P0074 Ambient Air Temperature Intermittant.

.

CIRCUIT OPERATION

• No circuit - IC internal test.

.

TECHNICAL DESCRIPTION

• Ambient air temperature is derived from the 

Intake air temperature.

.

DTC SET CONDITIONS 

Check Conditions

• Ambient air temperature is a modelled signal 

from the intake air temperature.

Judgement Criteria

• Signal out of calibrated threshold range.

• No MIL.

.

EOBD DRIVE CYCLE PATTERN

Refer to Diagnostic Function 

− EOBD Drive Cycle − 

P.13A-11

.

.

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

• Ambient air temperature was outside threshold 

values of -38.3

°C to 135°C

DIAGNOSIS

Required Special Tools:

• : Diagnostic Tool (MUT-III Sub Assembly)

• MB991824: V.C.I.

• MB991827: USB Cable

• MB991910: Main Harness A

CONNECTOR: B-10

B-10 (GR)

MASS

AIRFLOW

SENSOR

03DB217A

16DB400A

COVER

ENGINE

CONTROL

UNIT

AIR

CLEANER

1

2

3

4

1

2

3

4

1

2

3

4

1

2

3

4

AK303014

CONNECTOR: B-17X

MFI RELAY

MFI RELAY

FRONT OF VEHICLE

B-17X

AB

MULTIPOINT FUEL INJECTION (MPI) DIAGNOSIS

MULTIPOINT FUEL INJECTION (MPI)

13A-77

STEP 1. Using diagnostic tool , check data list item 5: 
Intake Air temperature Sensor.

CAUTION

To prevent damage to diagnostic tool , always turn the 
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting diagnostic tool .
(1) Connect diagnostic tool  to the data link connector.
(2) Start the engine and run at idle.
(3) Set diagnostic tool  to the data reading mode for item 5, 

Intake Air temperature Sensor.

(4) The intake air temperature sensor reading should be similar 

outside ambient air temperature.

(5) 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.00-14

.

NO :  Go to Step 2.

STEP 2. Test the EOBD drive cycle.
(1) Carry out a test drive with the drive cycle pattern. Refer to 

Diagnostic Function 

− EOBD Drive Cycle − 

P.13A-11

.

(2) Check the diagnostic trouble code (DTC).

Q: Is DTC P0074 set?

YES : Retry the troubleshooting.
NO :  The inspection is complete.

00DB076A

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

MULTIPOINT FUEL INJECTION (MPI) DIAGNOSIS

MULTIPOINT FUEL INJECTION (MPI)

13A-78

DTC P0101: Mass Airflow Circuit Range/Performance Problem.

CAUTION

If DTC P0101 has been set, TCL related DTC 
U1120 is also set. After P0101 has been diag-
nosed, don't forget to erase DTC U1120.

.

CIRCUIT OPERATION

• The mass airflow sensor power is supplied from 

the MPI relay (terminal No. 4), and the ground is 
provided on the ENGINE-ECU (terminal No. 11).

• 5-volt power is applied to the mass airflow sensor 

output terminal (terminal No. 4) from the 
ENGINE-ECU (terminal No. 11).

.

TECHNICAL DESCRIPTION

• While the engine is running, the mass airflow 

sensor outputs voltage which corresponds to the 
mass airflow rate.

• The ENGINE-ECU checks whether the voltage 

output by the mass airflow sensor while the 
engine is running is within a specified speed and 
load range.

.

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

Check Conditions

• Battery voltage is above 8.01 volts.

• Crankshaft revolution is above 150 r/min.

Judgement Criteria

• Air flow sensor output is below lower threshold 

(0-283.0 kg/h) for 4 seconds.

• MIL is activated immediately.

• No limp home mode.

.

CONNECTOR: B-10

B-10 (GR)

MASS

AIRFLOW

SENSOR

03DB217A

16DB400A

COVER

ENGINE

CONTROL

UNIT

AIR

CLEANER

1

2

3

4

1

2

3

4

1

2

3

4

1

2

3

4

AK303014

CONNECTOR: B-17X

MFI RELAY

MFI RELAY

FRONT OF VEHICLE

B-17X

AB

MULTIPOINT FUEL INJECTION (MPI) DIAGNOSIS

MULTIPOINT FUEL INJECTION (MPI)

13A-79

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

Check Conditions

• Battery voltage is above 8.01 volts.

• Crankshaft revolution is above 150 r/min.

Judgement Criteria

• Air flow sensor output is above upper threshold 

(40.9-903.0 kg/h) for 4 seconds.

• MIL is activated immediately.

• No limp home mode.

.

EOBD DRIVE CYCLE PATTERN

Refer to Diagnostic Function 

− EOBD Drive Cycle − 

P.13A-11

.

.

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

• Mass airflow sensor failed.

• Mass airflow sensor circuit harness damage, or 

connector damage.

• Refer to component locations GROUP-

70

• Refer to configuration diagrams GROUP-

80

• Refer to circuit diagrams GROUP-

90

DIAGNOSIS

Required Special Tools:

• : Diagnostic Tool (MUT-III Sub Assembly)

• MB991824: V.C.I.

• MB991827: USB Cable

• MB991910: Main Harness A

STEP 1. Using diagnostic tool , check data list item AA: 
Mass Airflow Sensor.

CAUTION

To prevent damage to diagnostic tool , always turn the 
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting diagnostic tool .
(1) Connect diagnostic tool  to the data link connector.
(2) Start the engine and run at idle.
(3) Set diagnostic tool  to the data reading mode for item AA, 

Mass Airflow Sensor.

(4) Warm up the engine to normal operating temperature: 80

°C 

to 95

°C (176°F to 203°F).

• The standard value during idling should be approxi-

mately 4.7 g/sec.

• When the engine is revved, the mass airflow rate should 

increase according to the increase in engine speed.

(5) 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.00-14

.

NO :  Replace the mass airflow sensor.Then go to Step 2.

00DB076A

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827