Discovery 2. Manual — part 497

ENGINE MANAGEMENT SYSTEM - V8

DESCRIPTION AND OPERATION 18-2-67

Function
The cruise control ECU activates the vacuum pump assembly to move the pneumatic actuator. This moves the
throttle to the set speed by adjusting the position of the throttle disc.

Accelerating while cruise control is active
There are three ways of increasing vehicle speed when cruise control is active:

l

Temporarily increase vehicle speed (e.g. when overtaking another vehicle).

l

Increase vehicle set speed in 1 mph (1.5 km/h) increments.

l

Increase vehicle set speed.

To temporarily increase vehicle speed press the accelerator pedal until the desired speed is reached. When the
accelerator pedal is released, the vehicle coasts back to the set speed. When it reaches the set speed, cruise control
operation continues.

To increase the vehicle set speed in 1 mph (1.5 km/h) increments, tap the SET+ switch. Each tap on the switch
increases vehicle speed.

To increase the vehicle set speed, press and hold the SET+ switch until the desired set speed is reached.

The vehicle set speed will increase if the following conditions are met:

l

The vehicle is under cruise control operation.

l

Vehicle speed is between 28 - 125 mph (45 - 200 km/h).

l

The brake pedal is not pressed.

l

The clutch pedal is not pressed (manual gearbox only).

l

The gearbox is not in park, reverse or neutral (automatic gearbox only).

Function
The vehicle responds as follows:

l

If the driver accelerates using the accelerator pedal, vehicle speed increases overriding pneumatic actuator
position. When the driver releases the accelerator pedal, the vehicle returns to the set speed.

l

If the SET+ switch is tapped, the driver increases the stored speed and vehicle speed by 1 mph (1.5 km/h) per
tap on the switch.

l

If the driver presses and holds the SET+ switch, the vehicle speed increases until the SET+ switch is released.
This becomes the new set speed for the cruise control ECU.

Switching off cruise control
Switching off cruise control allows the driver to regain control of vehicle speed. It erases the set road speed from the
cruise control ECU memory.

To switch off cruise control, press the cruise control master switch to the off position.

Function
When the cruise control master switch is turned off, the cruise control ECU switches off power to the vacuum pump
assembly. The vacuum dump valve opens releasing the vacuum in the pneumatic actuator, returning the throttle disc
to driver control via the accelerator pedal.

ENGINE MANAGEMENT SYSTEM - V8

18-2-68 DESCRIPTION AND OPERATION

ENGINE MANAGEMENT SYSTEM - V8

ADJUSTMENTS 18-2-69

ADJUSTMENTS

Cable - throttle

$% 19.20.05

Adjust

1. Loosen outer cable locknuts.
2. Adjust the rear locknut until it is in contact with

the back of the abutment bracket and the
throttle lever is in contact with the inner driven
lever.

3. Ensure that the driven lever remains in contact

with the throttle stop screw, (throttle closed).

4. Tighten cable front nut to lock cable to

abutment bracket.

Cable - cruise control

$% 19.75.11

Adjust

1. Ensure that the throttle cable is correctly

adjusted.

+

ENGINE MANAGEMENT SYSTEM -

V8, ADJUSTMENTS, Cable - throttle.

2. Loosen outer cable locknuts.
3. Adjust the rear locknut to obtain a 0.5 to 1.5

mm (0.019 to 0.060 in) gap, dimension 'A',
between the cruise control cable lever and the
throttle cable driven lever.

4. Tighten cable front locknut.

ENGINE MANAGEMENT SYSTEM - V8

18-2-70 ADJUSTMENTS