LR3/Disco 3
VISCOUS FAN CONTROL
The ECM controls an electronically controlled viscous coupled fan to provide engine cooling. The ECM supplies the fan
with a PWM signal that controls the amount of slippage of the fan, thus providing the correct amount of cooling fan speed
and airflow. The EMS uses a Hall Effect sensor to determine the fan speed.
STARTER RELAY
The starter relay is supplied with power from fuseable link 19 in the Battery Junction Box.
The ECM controls the starter relay by supplying a 12 volt signal to the relay coil when the ignition is in crank position. This
relies on the transmission gear position being either P or N.
CONDENSER FAN CONTROL
The ECM receives CAN messages from the ATC control module for idle speed adjustment and for cooling fan.
AirConCoolingRequest
This signal defines the level of cooling (from engine cooling fan(s)) required by the ATC system. Calibration within the
EMS determines the fan speed required, and which fans will be used, at each requested level.
AirConIdleSpeedRequest
This signal defines whether or not an increase in the engine idle speed is required by the ATC system. The amount of idle
speed increase is defined in the EMS calibration.
INTAKE MANIFOLD TUNING VALVE (IMTV)
The Intake Manifold Tuning Valve (IMTV) moves a plate within the inlet manifold to allow or block sonic pulses between
the split manifold halves. This, in effect, extends the inlet tracts for better low rpm torque. The IMTV is a two position valve
and is either fully open or fully closed. For additional information, refer to
Intake Air Distribution and Filtering
(303-12A
Intake Air Distribution and Filtering - 4.0L)
ECM ADAPTIONS
The ECM has the ability to adapt the values it uses to control certain outputs. This capability ensures the EMS can meet
emissions legislation and improve the refinement of the engine throughout its operating range.
The components which have adaptions associated with them are:
The APP sensor
The HO2S
The MAF/IAT sensor
The CKP sensor
Electric throttle body.
