Engine management system - Td5 (Cruise control): Description and operation

In the case of a VSS failure on vehicles with automatic transmissions the ECM applies default values derived from the EAT ECU. There is no default value for manual transmission vehicle.

The VSS can fail in the following ways: l Wiring short circuit to vehicle supply. l Wiring short circuit to vehicle earth. l Wiring open circuit.

In the event of a VSS failure any of the following symptoms may be observed: l Vehicle speed limiting disabled (manual transmission only). l Hill Descent Control (HDC) warning lamp on and audible warning.

Cruise control

All markets have a common cruise control system. The cruise control system, when activated, regulates vehicle speed. The ECM controls the cruise control system.

Cruise control activation Cruise control is a passive system, and must be activated by the driver. Cruise control is activated by switching on the cruise control master switch located on the instrument panel. A LED in the switch illuminates indicating cruise control is available. The driver must accelerate the vehicle to the desired speed using the accelerator pedal. When the desired speed is reached, cruise control can be activated by pressing the SET+ switch.

Cruise control will only activate if the following conditions are met: l Vehicle speed is above 22 mph (35 km/h). l The brake pedal is not pressed. l The clutch pedal is not pressed (manual transmission only). l The transmission is not in Park, Reverse or Neutral (automatic transmission only).

The ECM receives the set signal and determines the vehicle speed provided by the SLABS ECU. The ECM then maintains current road speed.

Cruise control cancellation Cancelling cruise control enables the driver to regain control of the vehicle speed by using the accelerator pedal.

Cruise control is cancelled if any of the following conditions occur: l The brake pedal is pressed. l The RES switch is pressed. l The clutch pedal is pressed (manual transmission only). l The cruise control master switch is switched off. l The transmission is placed in Park, Neutral, or Reverse (automatic transmission only).

The ECM cancels cruise control operation and returns it to the control of the accelerator pedal.

The set speed will be stored in the ECM unless: l The cruise control master switch is switched off. l The ignition is switched off.

If cruise control is deactivated using either of the above methods, the set speed will be erased from the memory of the ECM.