Ford Fiesta: Cruise Control / Cruise Control - System Operation and Component Description. Description and Operation

System Diagram

System Operation

Network Message Chart

  Network Input Messages - Instrument Panel Cluster (IPC)

  Network Input Messages - Powertrain Control Module (PCM)

Cruise Control Operation

The cruise control functions include:

• turning on the cruise control system.
• setting and maintaining the desired vehicle speed.
• accelerating the vehicle speed.
• coasting to a lower speed.
• resuming the prior vehicle speed.
• turning off the cruise control system.

Hard-wired inputs to the IPC are:

• Cruise control deactivator switch
• APP sensor
• CPP switch (manual transmission)

Hard-wired inputs to the PCM are:

• Brake pedal switch

Hard-wired outputs of the PCM are:

• Electronic Throttle Body (ETB) command

The vehicle speed is controlled by the IPC and the PCM through the Electronic Throttle Control (ETC) subsystem.

The cruise control system provides self-diagnostics. Cruise control is disabled anytime an error is detected in the system. No IPC indicator or message center messages are displayed when faults occur. Fault codes are logged by the IPC .

An Electronic Throttle Control (ETC) system fault also causes the cruise control system to be disabled. In this case, an Electronic Throttle Control (ETC) system powertrain malfunction (wrench) warning indicator is displayed.

Additionally, certain conditions cause the cruise control system to deactivate:

• Transmission gear selector is placed into a position other than D
• Cruise control set speed is overridden with the accelerator pedal for a period longer than 5 minutes
• Cruise control switch is pressed or stuck longer than 2 minutes
• ABS fault
• Traction control activation

Cruise Control Indicator

The cruise control indicator, located in the IPC , illuminates to indicate the cruise control system is active.

Steering Wheel Switch Function

Pressing and releasing the ON/OFF switch turns the cruise control system on. Pressing up (SET+) or down (SET-) on the SET switch while the vehicle is traveling accelerates or decelerates the vehicle to the desired speed and maintains that speed.

Pressing the SET switch up or down while in the active mode increases or decreases the maintained vehicle speed by 2 km/h (1 mph) per press. If the respective switch is pressed and held, the vehicle speed continues to accelerate or decelerate until the switch is released.

While the cruise control system is active, applying the brake pedal or pressing the CAN/RES switch puts the cruise control system into standby mode. Pressing the CAN/RES switch when the cruise control system is in standby mode causes the vehicle to accelerate to the last set speed. Resume does not function if the ON/OFF switch is pressed, the ignition is cycled OFF, or if the current vehicle speed is below the minimum operational speed.

Pressing and releasing the ON/OFF switch while the cruise control is active, or the ignition is cycled OFF, turns the cruise control system off.

Component Description

Steering Wheel Switches

The cruise control steering wheel mounted switches are momentary contact switches. Each steering wheel switch function corresponds to a specific resistance value. The switches are hard-wired to the IPC through the clockspring.

Brake Switch

The stoplamp switch and the cruise control deactivator switch are electrical inputs controlling the cruise control system. The stoplamp switch is a normally open switch that is hard-wired to the PCM . When the brake pedal is applied, the switch closes and applies a voltage signal to the PCM , deactivating the cruise control. The cruise control deactivator switch is a normally closed switch that is hard-wired to the IPC . When the brake pedal is applied, the switch opens and removes ground signal from the IPC . The IPC sends a HS-CAN message to the PCM to signal the brake pedal is applied. The PCM compares the inputs from the stoplamp switch and the cruise control deactivator switch. If a deviation occurs, the PCM sets a DTC and the cruise control system is deactivated.

Clutch Pedal Position (CPP) Switch

The CPP switch is used on vehicles equipped with a manual transaxle. When the clutch pedal is pressed with the cruise control system engaged, the normally open switch closes and provides a ground signal to the IPC . The IPC sends a HS-CAN message to the PCM to deactivate the cruise control system and place it in standby mode.