MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS
TSB Revision
MULTIPORT FUEL INJECTION (MFI) <3.0L>
13B-37
STEP 1. Using scan tool MB991502, check data list item 12:
Volume Air Flow Sensor.
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) Start the engine and run at idle.
(3) Set scan tool MB991502 to the data reading mode for item
12, Volume Air Flow 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 power supply voltage at volume air flow
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 the voltage normal?
YES :
Go to Step 5.
NO :
Go to Step 3.
AKX01177
16 PIN
MB991502
AB
AKX01514 AD
B-14 CONNECTOR
HARNESS SIDE VIEW
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