ENGINE MANAGEMENT SYSTEM - V8: DESCRIPTION AND OPERATION (page 2 of 3)

ENGINE MANAGEMENT SYSTEM - V8

DESCRIPTION AND OPERATION 18-2-75

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

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

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

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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:

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The vehicle is under cruise control operation.

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

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The brake pedal is not pressed.

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

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

Function
The vehicle responds as follows:

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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.

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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.

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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.