DIAGNOSTICS
SERVICE MANUAL NUMBER 24
Page 5G-84
90-861327--1 OCTOBER 1999
Code 45 (1 of 2): Ignition Coil Driver Fault
D
E
F
C
B
A
121 WHT
121 WHT
121 WHT
901 TAN
585 TAN/WHT
208 BRN
+
–
TEMP SENDER
IGNITION
COIL
3 PNK
TO IGN
B+
29 DK GRN
ECM
MEFI 3
J1-2
J2-20
J2-8
J1-26
902 RED
CIRCUIT DESCRIPTION:
On MEFI 3 product, the coil driver circuitry is integrated into the ECM. When the engine is
running, a diagnostic check of the coil drive circuitry is constantly taking place. If the diag-
nostic system detects excessive current to the coil through CKT 121, a fault code will set
although the engine should continue to operate.
DIAGNOSTIC AIDS
Check for the following conditions:
•
Poor connection at ECM. Inspect harness connectors for backed out terminals,
improper mating, broken locks, improperly formed or damaged terminals, and poor
terminal to wire connection.
•
Damaged harness. Inspect the wiring harness for damage.
•
Shorted CKT 121 or tach lead in harness.
•
Damaged ignition coil or improper coil. The ignition system is calibrated for Mercury
approved coils only.
Index