MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS
TSB Revision
MULTIPORT FUEL INJECTION (MFI) <3.0L>
13B-634
.
CIRCUIT OPERATION
•
The battery positive voltage is applied on the igni-
tion coil by the ignition switch-IG.
•
When the ECM <M/T> or PCM <A/T> turns the
power transistor in the ECM <M/T> or PCM <A/
T> "OFF", battery positive voltage is applied on
the ignition power transistor (terminals 3), and the
ignition power transistor turns "ON".
•
When the ignition power transistor turns on, the
ignition coil's primary circuit is grounded by the
ignition power transistor terminal 4. Then the pri-
mary current flows to the ignition coil.
.
TROUBLESHOOTING HINTS (The most likely
causes for this case:)
•
Malfunction of the ignition coil.
•
Malfunction of the ignition power transistor.
•
Improper connector contact, open circuit or short-
circuited harness wire.
•
Malfunction of the ECM <M/T> or PCM <A/T>.
AK000217AB
AK000217
CONNECTOR: B-22
AK101421AD
CONNECTOR: C-111
AK000225
CONNECTOR : C-51<M/T>, C-52<A/T>
C-52
C-51
PCM<A/T>
ECM<M/T>
AJ
AC101151
AC101133
AC
ENGINE SPEED
DETECTION
CONNECTOR
CONNECTOR: A-12X
AK101420AD
CONNECTOR: C-108
AK000345AE
CONNECTOR:C-89
AK000219
CONNECTOR:C-87
AC
AK000312AJ
CONNECTOR:C-07