Cruise Control System - Speed Control: Overview Ford Focus II рестайлинг

The speed control system consists of the following components

1. Electronically-controlled throttle body
2. Clutch pedal speed control deactivator switch (manual transaxle only)
3. PCM
4. Speed control switches
5. Speed control indicator
6. Speed control deactivator switch (part of the stoplamp switch)
7. Stoplamp switch

When the speed control system is activated, a selected vehicle speed above 48 km/h (30 mph) to the maximum limited vehicle speed can be maintained without pressing the accelerator pedal. The speed control does not work at speeds below 48 km/h (30 mph).

It is normal for the engine RPM to increase slightly and then drop off slowly when the clutch pedal is applied during operation.

SPECIAL TOOLS - SPEED CONTROL Illustration Tool Name Tool Number 73III Automotive Meter 105-R0057 or equivalent Vehicle Communication Module (VCM) and Integrated Diagnostic System (IDS) software with appropriate hardware, or equivalent scan tool - Restraint System Diagnostic Tool (2 required) 418-F395 Flex Probe Kit 105-R025C or equivalent

Scheme 1

Scheme 2

Scheme 3

Principles of Operation

The speed control system is controlled by the PCM. The speed control system is designed to maintain a selected vehicle speed between 48 km/h (30 mph) and the maximum limited vehicle speed. The speed control system is controlled by the steering wheel mounted switches (ON, OFF, SET+, SET-, and RESUME), the stoplamp switch, the clutch pedal speed control deactivator switch (manual transaxle), and the speed control deactivator switch (part of the stoplamp switch). The steering wheel mounted switches are hardwired to the PCM through the clockspring.

The speed control functions include

1. turning on the speed control system.
2. setting and maintaining the desired vehicle speed.
3. accelerating the vehicle speed.
4. coasting down to a lower speed.
5. resuming the prior vehicle speed.
6. turning off the vehicle speed control system.

Pressing and releasing the ON switch turns the speed control system on. Pressing and releasing the SET+ or SET- switch while the vehicle is traveling at the desired speed activates the speed control system.

Tapping the SET+ or the SET- switch while in the set mode respectively, increases or decreases the maintained vehicle speed by 1.6 km/h (1 mph) per tap. If the respective button is pressed and held, the vehicle speed continues to accelerate or decelerate until the button is released.

Pressing and releasing the OFF switch, or turning the ignition switch to the OFF position, turns the speed control system off. Applying the brake pedal puts the speed control system into the STANDBY mode. Pressing the RESUME button, when the speed control system is in the STANDBY mode causes the vehicle to accelerate to the last set speed. Resume does not function if the OFF button is pressed, the ignition switch is in the OFF position, or if the current vehicle speed is below the minimum operational speed.

The clutch pedal speed control deactivator switch is used on vehicles equipped with a manual transaxle. When the clutch pedal is applied with the vehicle speed control system engaged, the normally closed switch opens and signals the PCM to deactivate the speed control.

Whenever the speed control system is engaged and active, a speed control icon on the instrument cluster (IC) is illuminated.

The speed control deactivator switch is provided as an additional safety feature. Normally, when the brake pedal is applied, an electrical signal from the stoplamp circuit to the PCM deactivates the system. Under increased brake pedal effort, the speed control deactivator switch opens and removes the voltage from the PCM input circuit, releasing the throttle.

The clockspring provides the electrical interface between the steering column wiring and the speed control switches in the steering wheel.

The inputs to the PCM are

1. Output shaft speed (OSS) sensor
2. Digital transmission range (TR) sensor (automatic transaxle)
3. Speed control switch(es)
4. Clutch pedal speed control deactivator switch (manual transaxle)
5. Speed control deactivator switch (part of the stoplamp switch)
6. Stoplamp switch
7. Accelerator pedal position sensor

The outputs of the PCM are

1. Speed control indicator lamp
2. Throttle command

The speed control system throttle position is completely controlled by the PCM through the electronic-controlled throttle body. Speed control electronics are contained entirely within the electronic throttle control (ETC) subsystem.

When the speed control system is active, the PCM corrects for deviations in the actual vehicle speed by proportionally moving the throttle plate. The PCM modulates the throttle to minimize error between the actual vehicle speed and the desired speed.

The PCM strategy uses the throttle control for smooth accelerations.

The PCM sends a serial message over the controller area network (CAN) to the IC whenever the speed control telltale is turned on or off.

In the event of an OFF command or a deactivation request from the speed control deactivator switch, the speed control system carries out a hard deactivation and immediately returns the throttle to the idle position.

The speed control system provides self-diagnostics. Speed control is disabled anytime an error is detected in the system. No IC telltale or message center messages are displayed when faults occur. Fault codes are logged by the PCM.

An ETC system fault also causes the speed control system to be disabled. In this case, an ETC system warning telltale (wrench light) or a message center message is displayed.

Additionally, the following conditions cause the speed control system to deactivate

1. Transmission gear selector in a position other than D or OD (automatic transaxle)
2. Clutch pedal is pressed (manual transaxle)
3. Speed control set speed is over-ridden with the accelerator pedal for a period longer than 5 minutes
4. Parking brake is applied (manual transaxle)
5. Vehicle speed loss from set speed of greater than 16 km/h (10 mph) occurs
6. Vehicle speed falls below the minimum allowable limit of 48 km/h (30 mph)
7. Speed control switch pressed or stuck longer than 2 minutes

Normal Operation

The PCM sends a signal through circuit VES10 (WH) to the speed control switches, which passes through the clockspring. The signal is grounded by the PCM circuit RES08 (GN/BN) and the clockspring. The stoplamp switch sends a voltage signal through circuit CCB08 (VT/WH) to the PCM when the brake pedal is applied, and deactivates the speed control, if engaged.

Vehicles equipped with a manual transaxle have an additional clutch pedal speed control deactivator switch. The PCM sends a signal to the clutch pedal speed control deactivator switch through circuit CE904 (GN/VT). The clutch pedal speed control deactivator switch, normally closed with the clutch pedal released, routes the signal to ground through circuit GD134 (BK/VT). When the clutch pedal is applied, the clutch pedal speed control deactivator switch moves to the open position causing the PCM to lose the ground signal and deactivate the speed control.

The speed control deactivator switch (part of the stoplamp switch) interrupts circuit CES09 (VT/OG), removing the voltage signal to the PCM when the brake pedal is applied. This is a redundant signal to the PCM.

This pinpoint test is intended to diagnose the following

1. PCM not configured for speed control
2. Wiring, terminals or connectors
3. Clockspring
4. Digital transmission range (TR) sensor (automatic transaxle)
5. Speed control switches
6. Stoplamp switch
7. Clutch pedal speed control deactivator switch (manual transaxle)
8. Vehicle speed signal concern
9. PCM

When the brake pedal is applied, voltage is sent to the PCM from the stoplamp switch through circuit CCB08 (VT/WH).

The speed control deactivator switch (part of the stoplamp switch) interrupts circuit CES09 (VT/OG), removing the voltage signal to the PCM when the brake pedal is applied. This is a redundant signal to the PCM.

1. DTC P1572 (Brake Pedal Switch Circuit) - sets when the PCM does not sense the correct sequence of the brake pedal input signal from both the speed control deactivator and stoplamp switches when the brake pedal is pressed and released.
2. DTC P1703 (Brake Switch Out of Self-Test Range) - sets when there is an open or short in the deactivator switch circuits or when there is an open or short in the stoplamp circuits.

This pinpoint test is intended to diagnose the following

1. Fuse
2. Wiring, terminals or connectors
3. Speed control deactivator switch (part of the stoplamp switch)
4. ABS module
5. PCM

The PCM sends a signal through circuit VES10 (WH) to the speed control switches, which passes through the clockspring. The signal is grounded by the PCM through circuit RES08 (GN/BN) and the clockspring.

1. DTC P0579 (Cruise Control Multifunction Input A Circuit Range/Performance) - may set when a speed control switch is stuck or the switch circuits are open, shorted to voltage or shorted to ground.
2. DTC P0581 (Cruise Control Multifunction Circuit High) - sets when the speed control switch circuits are shorted to voltage or open.

This pinpoint test is intended to diagnose the following

1. Wiring, terminals or connectors
2. Clockspring
3. Speed control switch
4. PCM

The clutch pedal speed control deactivator switch, normally closed, supplies a ground signal to the PCM through circuit CE904 (GN/VT). When the clutch pedal is applied, the clutch pedal speed control deactivator switch moves to the open position causing the PCM to lose the ground signal and deactivate the speed control. Ground for the clutch pedal speed control deactivator switch is supplied by circuit GD134 (BK/VT).

This pinpoint test is intended to diagnose the following

1. Wiring, terminals or connectors
2. Clutch pedal speed control deactivator switch (manual transaxle)
3. PCM

See also:
• AUTOMATIC TRANSAXLE/TRANSMISSION - 4F27E