Ford Workshop Service and Repair Manuals

Electronic Stability Program (ESP)

The stability assist adds a further function known as electronic stability program (ESP) to the traction control system. Whereas the traction control system function controls wheel slip during braking and acceleration (longitudinal dynamics), the active yaw control stabilizes the vehicle about its vertical axis. The ESP traction control function is not limited to 40 km/h (25 mph) and functions automatically in all driving conditions.

Sensors measure the position of the steering wheel, the pressure in the brake master cylinder, the yaw velocity (yaw rate) and the acceleration transverse to the vehicle (lateral acceleration). This makes it possible to compare the driver's intention with the momentary vehicle behaviour so that in the event of the vehicle becoming unstable the stability assist system can initiate the appropriate corrective action.

The stability assist recognizes critical driving conditions, such as panic reactions in dangerous situations, and stabilizes the vehicle by individually braking each wheel and engine control intervention without the need to a actuate the brake or the accelerator pedal.

To control wheel slip, the ESP reads engine torque data from the high speed CAN bus and requests changes. If this data is faulted or not available, the ESP will not function and the warning lamp will be permanently on.

A driver disable switch with an integral indicator lamp is provided with the ESP.

Hydraulic Brake Assist (HBA)

An hydraulic brake assist (HBA) function has been added to the stability assist software to enhance the brake system performance in emergency braking situations at reduced pedal force during critical situations. When the HBA is activated, the anti-lock brake system (ABS) is immediately employed to optimise the stopping distance.

Active Roll-Over Mitigation (ARM)

During severe emergency avoidance manoeuvres, with the vehicle in a critical condition, the ARM function of the ESP will use high front wheel brake pressure to stabilise the vehicle and reduce the risk of roll-over. ARM will remain active even when ESP is disabled by the driver.

Motor-Induced Slip Regulation (MSR)

During downshifting, or when releasing the accelerator pedal on a slippery surface, the engine braking effect can cause the wheels to lock. The MSR function of the ESP corrects this behaviour by increasing the engine torque to a safe value. This may be noticed by a driver as a slight increase, or a slow ramp down, of engine rpm during deceleration.

Hill Launch Assist (HLA) - Vehicles built 08/2007 onwards

The hill launch assist supports the driver when starting the vehicle on a gradient by preventing the vehicle from unintentionally rolling backwards. The system is integrated in the stability assist and uses the vehicle service brakes.

The instrument cluster has an additional indicator lamp for the HLA system. The hill launch assist indicator illuminates during activation of the system, while driving. After switching on the ignition, the indicator illuminates for three second, if the system is enabled. During a malfunction, the system switches off and will not illuminate while driving.

The service technician has the opportunity to disable or enable the system at the customer's request.

For the manual disable or enable the following steps are to be accomplished:

• 1. Ignition on.

• 2. Clutch pedal, brake pedal and accelerator pedal depressed and hold for 8 seconds.

• 3. The HLA indicator will flash for 3 seconds.

• 4. Release the pedals when the indicator flashes. Holding for a longer period (up to 24s) can result in the service reminder inadvertently being reset.

Function

The hill launch assist is activated when,

• the engine is running,
• the brake pedal is actuated,
• the vehicle is at a standstill for at least 1 second,
• the clutch pedal is pressed,
• the parking brake is NOT applied,
• the vehicle is located on an upward gradient of at least 3 %, or
• the vehicle is on a downward gradient of at least 3 % and reverse gear is engaged,
• the function has not been deactivated,
• the passenger and cargo doors must be closed,
• no function-relevant fault has been stored in the system.

The brake pressure generated when the brake is actuated is "locked" at the wheel brake with the help of the stability assist isolating valves. The high-pressure pump is not activated.

When there is sufficient engine torque to drive off uphill, the brake pressure is immediately released and the HLA indicator lamp goes out.

If the driver removes his foot from the brake and does not attempt to drive off the brake pressure is slowly released after 2 seconds and the HLA telltale goes out.

If the driver attempts to drive off (e.g. by pressing the accelerator pedal) the hold time is extended.

The tension occurring in the chassis as a result of the slow release also signals the release of the brake.

The activated hill launch assist is automatically deactivated (engaged brake is released) when

• the clutch pedal is released or,
• the vehicle does not pull away within approx. 2 seconds or,
• the engine is switched off or stalls,
• any door is opened (including cargo doors),
• the parking brake is applied,
• Reverse gear is selected when facing uphill,
• Reverse gear is de-selected when facing downhill.

Inclination sensor

For the purpose of road inclination detection, an additional inclination sensor is installed in the housing of the stability assist yaw rate/ lateral acceleration sensor.

Operation of the inclination sensor corresponds to that of a (lateral) acceleration sensor, as the downhill-slope force occurring on gradients acts in the same way as an acceleration force.