Mitsubishi Eclipse. Manual - part 375

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-43

DTC SET CONDITIONS

Logic Flow Chart

.

Check Conditions

• Engine speed is higher than 500 r/min.

Judgement Criteria

• Volume airflow sensor output frequency has con-

tinued to be 3.3 Hz or lower for 2 seconds.

.

OBD-ll DRIVE CYCLE PATTERN
Refer to Diagnostic Function 

− OBD-ll Drive Cycle − 

Procedure 6 

− Other Monitor 

P.13B-7

.

.

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

• Volume airflow sensor failed.

• Open or shorted volume airflow sensor circuit,  

harness damage, or connector damage.

• ECM failed. <M/T>

• PCM failed. <A/T>

DIAGNOSIS

Required Special Tools:

• MB991958: Scan Tool (MUT-III Sub Assembly)

• MB991824: V.C.I.

• MB991827: USB Cable

• MB991911: Main Harness B

START

MONITORING

CONDITIONS

END

NO

NO

NO

YES

YES

YES

MALFUNCTION

GOOD

OUTPUT FREQUENCY

< 3.3Hz

CONTINUOUS

FAILURE FOR 2 secs

AK301413

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-44

STEP 1. Using scan tool MB991958, check data list item 12: 
Volume Airflow Sensor.

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) Start the engine and run at idle.
(3) Set scan tool MB991958 to the data reading mode for item 

12, Volume Airflow Sensor.

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

°C 

to 96

°C (176°F to 205°F).

• The standard value during idling should be 10 Hz or 

more.

• When the engine is revved, the frequency 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 

P.00-6

.

NO :  Go to Step 2.

STEP 2. Check the power supply voltage at volume airflow 
sensor connector B-14 by backprobing.
(1) Do not disconnect the connector B-14.
(2) Turn the ignition switch to the "ON" position.

(3) Measure the voltage between terminal 4 and ground by 

backprobing.

• Voltage should be battery positive voltage.

(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is battery positive voltage (approximately 12 volts) 

present?
YES : Go to Step 5.
NO :  Go to Step 3.

AK300810

AB

MB991911

16-PIN

MB991827

MB991824 

AK300078

3

4

5

1

2

6

7

CONNECTOR: B-14

AB

B-14 (B)

HARNESS 
CONNECTOR:
COMPONENT SIDE

AKX01514 AH

1 2 3 4 5 6 7

B-14 HARNESS
CONNECTOR:
HARNESS SIDE

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-45

STEP 3. Check the power supply voltage at volume airflow 
sensor harness side connector B-14.
(1) Disconnect the connector B-14 and measure at the harness 

side.

(2) Turn the ignition switch to the "ON" position.

(3) Measure the voltage between terminal 4 and ground.

• Voltage should be battery positive voltage.

(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is battery positive voltage (approximately 12 volts) 

present?
YES : Go to Step 4.
NO :   Repair harness wire between MFI relay connector 

A-18X (terminal No. 4) and volume airflow sensor 
connector B-14 (terminal No. 4) because of open 
circuit or short circuit to ground. Then go to Step 13.

STEP 4. Check connector B-14 at the volume airflow 
sensor for damage.
Q: Is the connector in good condition?

YES : Repair harness wire between MFI relay connector 

A-18X (terminal No. 4) and volume airflow sensor 
connector B-14 (terminal No. 4) because of harness 
damage. Then go to Step 13.

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

Connector Inspection 

P.00E-2

. Then go to Step 13.

STEP 5. Check connector B-14 at volume airflow sensor 
for damage.
Q: Is the connector in good condition?

YES : Go to Step 6.
NO :  Repair or replace it. Refer to GROUP 00E, Harness 

Connector Inspection 

P.00E-2

. Then go to Step 13.

AK300078

3

4

5

1

2

6

7

CONNECTOR: B-14

AB

B-14 (B)

HARNESS 
CONNECTOR:
COMPONENT SIDE

AKX01405

B-14 HERNESS CONNECTOR: 
COMPONENT SIDE

7 6 5 4 3 2 1

AH

AK300078

3

4

5

1

2

6

7

CONNECTOR: B-14

AB

B-14 (B)

HARNESS 
CONNECTOR:
COMPONENT SIDE

AK300078

3

4

5

1

2

6

7

CONNECTOR: B-14

AB

B-14 (B)

HARNESS 
CONNECTOR:
COMPONENT SIDE

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-46

STEP 6. Check the sensor supply voltage at volume airflow 
sensor harness side connector B-14.
(1) Disconnect the connector B-14 and measure at the harness 

side.

(2) Turn the ignition switch to the "ON" position.

(3) Measure the voltage between terminal 3 and ground.

•  Voltage should be between 4.8 and 5.2 volts.

(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the measured voltage between 4.8 and 5.2 volts?

YES : Go to Step 9.
NO :  Go to Step 7.

AK300078

3

4

5

1

2

6

7

CONNECTOR: B-14

AB

B-14 (B)

HARNESS 
CONNECTOR:
COMPONENT SIDE

AKX01406 AG

7 6 5 4 3 2 1

B-14 HARNESS 
CONNECTOR: 
COMPONENT SIDE