MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS
TSB Revision
MULTIPORT FUEL INJECTION (MFI) <3.0L>
13B-36
.
CIRCUIT OPERATION
•
The volume air flow sensor power is supplied
from the MFI relay (terminal 4), and the ground is
provided on the ECM (terminal 34) <M/T> or
PCM (terminal 16) <A/T>.
•
5-volt power is applied to the volume air flow sen-
sor output terminal (terminal 3) from the ECM
(terminal 61) <M/T> or PCM (terminal 65) <A/T>.
The volume air flow sensor generates a pulse
signal when the output terminal and ground are
opened/closed (opened/short).
.
TECHNICAL DESCRIPTION
•
While the engine is running, the volume air flow
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
air flow sensor while the engine is running is at or
above the set value.
.
DTC SET CONDITIONS
Check Conditions
•
Engine speed is higher than 500 r/min.
Judgement Criteria
•
Volume air flow sensor output frequency has con-
tinued to be 3.3 Hz or lower for 2 seconds.
.
TROUBLESHOOTING HINTS (The most likely
causes for this code to be set are:)
•
Volume air flow sensor failed.
•
Open or shorted volume air flow sensor circuit, or
loose connector.
•
ECM failed. <M/T>
•
PCM failed. <A/T>
•
Air leak between volume air flow sensor and
throttle body.
DIAGNOSIS
Required Special Tools
•
MB991502: Scan Tool (MUT-II)
AK101363AB
MFI RELAY
CONNECTOR: A-18X
ACX02480
CONNECTOR : B-14
AC
VOLUME AIR
FLOW SENSOR
AK000225
C-52
C-55
C-51
C-58
CONNECTORS:C-51,C-58<M/T>
C-52,C-55<A/T>
ECM<M/T>
PCM<A/T>
AH