Discovery II
ENGINE MANAGEMENT SYSTEM - V8
DESCRIPTION AND OPERATION 18-2-41
Input/Output
Input to the low tension side of the ignition coils comes from Fuse 14 located in the passenger compartment fuse box.
This fuse provides battery power for two ignition coils.
It is possible to test both primary and secondary coils of the ignition coils for resistance using a multimeter as follows:
l
Expected primary coil resistance: 0.5
±
0.05
Ω
at 20
°
C (68
°
F).
l
Expected secondary coil resistance: 13.3
±
1.3 k
Ω
at 20
°
C (68
°
F).
The ECM provides the earth control for each coil on separate pins as follows:
LH Bank (cylinders 1, 3, 5, 7)
l
Cylinder 1 - pin 6 of connector C0638 of the ECM multiplug.
l
Cylinder 3 - pin 2 of connector C0638 of the ECM multiplug.
l
Cylinder 5 - pin 8 of connector C0638 of the ECM multiplug.
l
Cylinder 7 - pin 7 of connector C0638 of the ECM multiplug.
RH Bank (cylinders 2, 4, 6, 8)
l
Cylinder 2 - pin 2 of connector C0638 of the ECM multiplug.
l
Cylinder 4 - pin 7 of connector C0638 of the ECM multiplug.
l
Cylinder 6 - pin 6 of connector C0638 of the ECM multiplug.
l
Cylinder 8 - pin 8 of connector C0638 of the ECM multiplug.
The ignition coil can fail the following ways or supply incorrect signal:
l
Coil open circuit.
l
Short circuit to vehicle supply.
l
Short circuit to vehicle earth.
l
Faulty component.
In the event of ignition coil failure any of the following symptoms may be observed:
l
Engine misfire on specific cylinders.
l
Engine will not start.
