Discovery II
ENGINE MANAGEMENT SYSTEM - V8
18-2-44 DESCRIPTION AND OPERATION
High tension (ht) leads
The ht leads are located on top of the engine, below the plenum chamber. Their function is to transfer the ht voltage
generated by the ignition coils to the spark plugs in the engine.
Input/Output
The input to the ht lead is ht voltage from the ignition coil pack. The ht lead then supplies this voltage to the spark
plug. Output ht voltage is used by the spark plugs to ignite the air/fuel mixture in the combustion chamber.
The ht leads can fail in the following ways:
l
Connector/ Wiring fault.
l
Faulty component causing spark tracking to chassis earth.
l
Damage to ht leads during component removal.
In the event of a ht lead failure the following symptom may be observed:
l
Misfire on specific cylinder.
All ignition system related faults are diagnosed by the misfire detection system and its fault codes.
Hill Decent Control (HDC)
Refer to Brakes for description of the hill descent control.
BRAKES, DESCRIPTION AND OPERATION, Description.
High/Low ratio switch
Refer to Transfer Box for description of the high/ low ratio switch transfer box components.
TRANSFER BOX - LT230SE, DESCRIPTION AND OPERATION, Description.
