DIAGNOSTICS
SERVICE MANUAL NUMBER 24
90-861327--1 OCTOBER 1999
Page 5G-47
MEFI 3 (EXCEPT BLACK SCORPION)
D
E
F
C
B
A
439 PNK
121 WHT
121 WHT
121 WHT
901 TAN
29 DK GRN
585 TAN/WHT
208 BRN
+
–
902 RED
430 PPL/WHT
TEMP SENDER
IGNITION
COIL
DISTRIBUTOR
3 PNK
WHT/RED
WHT/GRN
IGNITION
ECM
MEFI 1
MEFI 2
MEFI 3
J2-10
J1-2
B+
MEFI 1
MEFI 2
MEFI 3
J2-20
J2-8
J1-26
CIRCUIT DESCRIPTION:
Several discrete switch inputs are utilized by the fuel injection system to identify abnormal
conditions that may affect engine operation. A pull-up switch is currently used in conjunction
with the ECM to detect critical conditions to engine operation.
If a discrete switch changes states from its normal at-rest position, that is normally open to
closed (or closed to open), the ECM senses a change in voltage and responds by activating
the audio warning system.
DIAGNOSTIC AIDS:
•
Check engine oil and gear lube levels. Check transmission fluid for overheat condi-
tion.
An intermittent problem may be caused by a poor or corroded connection, rubbed through
wire connection, or a wire that is broken inside the insulation.
Index