Mitsubishi Eclipse. Manual — part 372
MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS
TSB Revision
MULTIPORT FUEL INJECTION (MFI) <3.0L>
13B-31
.
CIRCUIT OPERATION
• The volume airflow sensor power is supplied from
the MFI relay (terminal No. 4), and the ground is
provided on the ECM (terminal No. 34) <M/T> or
PCM (terminal No. 16) <A/T>.
• 5-volt power is applied to the volume airflow sen-
sor output terminal (terminal No. 3) from the ECM
(terminal No. 61) <M/T> or PCM (terminal No. 65)
<A/T>. The volume airflow sensor generates a
pulse signal when the output terminal and ground
are opened/closed (opened/short).
• 6-9 volts power is applied to the PCM (terminal
No. 19) from the volume airflow sensor (terminal
No. 7).
• The PCM (terminal No. 19) controls the airflow
sensror reset signal by turning the power transis-
tor within the PCM to "ON" and "OFF" position.
.
TECHNICAL DESCRIPTION
• While the engine is running, the volume airflow
sensor outputs a pulse signal which corresponds
to the volume of air flow.
• The ECM <M/T> or PCM <A/T> checks whether
the frequency of this signal output by the volume
airflow sensor while the engine is running is at or
above the set value.
• When the throttle position sensor output voltage
is low, the ECM <M/T> or PCM <A/T> causes the
power transistor to be "ON" to send an volume
airflow sensor reset signal to the volume airflow
sensor. In response to the reset signal, the vol-
ume airflow sensor resets the filter circuit and
improves the ability of the volume airflow sensor
to measure the amount of air in a small air intake
region.
.
DESCRIPTIONS OF MONITOR METHODS
Compare load value with volume airflow sensor out-
put voltage.
.
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)
• Throttle position sensor
.
AK300121
MFI RELAY
CONNECTOR: A-18X
AB
A-18X
AK300053
CONNECTOR: B-14
VOLUME AIRFLOW
SENSOR
AB
B-14 (B)
AK300091
CONNECTORS: C-51, C-58 <M/T>
ECM
AB
C-51 (GR)
C-58 (GR)
AK300244
CONNECTORS: C-52, C-55 <A/T>
AB
PCM
C-52 (GR)
C-55 (GR)
MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS
TSB Revision
MULTIPORT FUEL INJECTION (MFI) <3.0L>
13B-32
DTC SET CONDITIONS <Range/Performance problem - high input>
Logic Flow Chart
.
Check Conditions
• Throttle position sensor output voltage is 1.5 volts
or higher.
• Engine speed is higher than 2,000 r/min.
Judgement Criteria
• Volume airflow sensor output frequency has con-
tinued to be 60 Hz or lower for 2 seconds.
.
START
MONITORING
CONDITIONS
END
NO
YES
NO
YES
NO
YES
MALFUNCTION
GOOD
OUTPUT FREQUENCY
> =800Hz
CONTINUOUS
FAILURE FOR 2 secs
AK301411
MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS
TSB Revision
MULTIPORT FUEL INJECTION (MFI) <3.0L>
13B-33
DTC SET CONDITIONS <Range/Performance problem - low input>
Logic Flow Chart
Check Conditions
• Throttle position sensor output voltage is 2 volts
or lower.
• Engine speed is lower than 2,000 r/min.
Judgement Criteria
• Volume airflow sensor output frequency has con-
tinued to be 800 Hz or higher for 2 seconds.
.
OBD-ll DRIVE CYCLE PATTERN
Refer to, Diagnostic Function
− OBD-ll Drive Cycle −
Procedure 6
.
.
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
YES
NO
YES
NO
YES
MALFUNCTION
GOOD
OUTPUT FREQUENCY
< =60Hz
CONTINUOUS
FAILURE FOR 2 secs
AK301412
MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS
TSB Revision
MULTIPORT FUEL INJECTION (MFI) <3.0L>
13B-34
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
NO : Go to Step 2.
STEP 2. Check the reset signal 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 7 and ground by
backprobing.
• Voltage should be between 6.0 and 9.0 volts.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the measured voltage between 6.0 and 9.0 volts?
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
AKX01515 AG
B-14 HARNESS
CONNECTOR:
HARNESS SIDE
1 2 3 4 5 6 7
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