FORD SCORPIO models up to 1/92 are equipped with brakes with ABS TEVES MK II. From 2/92 cars are equipped with brakes with ABS TEVES MK IV (models with a 24-valve engine with a displacement of 2.9 liters and with a diesel engine from 2/92 to 8/94 were equipped with upgraded brakes TEVES MK II).
The TEVES MK II brake system works with a hydraulic unit that replaces the conventional brake master cylinder with a vacuum-operated brake booster.
The TEVES MK IV brake system consists of a conventional brake master cylinder with a vacuum-operated brake booster and a separate, electronically controlled valve block with a pump
ABS prevents the wheels from locking during hard braking. Thanks to this, the car remains steerable during hard braking to a complete stop.
Wheel speed sensors are installed on each wheel to measure the speed of the wheels. Based on the signals from the individual sensors, the electronic control unit calculates an average speed that roughly corresponds to the average vehicle speed. By comparing the speed of an individual wheel and the average speed of all the wheels, the control unit determines the slip state of an individual wheel and thereby determines how close that wheel is to blocking. As soon as the wheel approaches the lock state, the hydraulic system, based on signals from the control unit, keeps the fluid pressure constant. This means that the pressure in the brake caliper does not increase even when the brake pedal is pressed even harder. If the blocking tendency persists later, the fluid pressure is reduced by opening the outlet valve. However, it is reduced only so much that the wheel receives a slight acceleration, after which the pressure is again maintained unchanged.
The rear wheels have a common control, the pressure in the hydraulic system is determined by the rear wheel with the greatest tendency to slip.
If the wheel acceleration exceeds a certain value, the pressure in the hydraulic system begins to rise again, but not higher than the value present in the entire system.
This process is repeated under hard braking for each wheel until the brake pedal is released or until the vehicle comes to near standstill (5-7 km/h).
ASR/EBV systems on vehicles since 9/94
ASR system (Antriebsschlupfregelung): With the help of an electronic drive wheel slip control system, during acceleration, the slipping wheel is braked, and the torque is directed to the wheels with traction.
The electronic system monitors the slip of wheels that are prone to spinning and reacts instantly and individually by immediately creating and directly modulating brake pressure on the respective wheels. This ensures that the maximum transmitted traction force is always used, in extreme cases even on only one wheel. The self-acting ASR system uses many ABS components. The system functions during acceleration and is automatically deactivated when the vehicle reaches a speed of 50 km/h. A particular advantage of this method of improving traction: this method does not adversely affect either the vehicle's dynamic qualities or driving comfort.
EBV system (elektronische Bremskraftver-teilung) The electronic brake force distribution distributes the brake force to the rear wheels using the hydraulics of the ABS system. Since the electronic control of the EBV system is more sensitive than the mechanically acting brake force regulator. the control range becomes much wider.
In a straight line, the rear wheel brakes absorb the full brake load. In order to ensure the stability of the vehicle when braking on a corner, the braking effect of the rear axle must be reduced. Using the ABS speed sensors, the EBV system determines whether the vehicle is moving straight ahead or in a curve. When driving on a curve, the brake pressure for the rear axle is reduced. This allows the rear wheels to take up the maximum side-slip force.
Notes on ABS/EBV/ASR systems
The battery switch in the electronic control unit ensures that, in the event of a defect, (e.g. broken wire) or if the operating voltage is too low (battery voltage below 10.5 volts) ABS turned itself off. In this case, a yellow warning signal lights up on the instrument panel while driving. that ABS is deactivated At the same time, the EBV system is also deactivated. The conventional braking system remains in working condition. The car behaves when braking in this case as if the ABS system was not installed on it.
Safety instructions: If the red brake warning light on the instrument panel lights up while driving, stop the vehicle immediately and find out the cause. The reason for the warning light to come on may be, for example, an insufficient amount of brake fluid or a tightened hand brake. When the EBV system fails, the yellow ABS warning light and the red brake warning light come on simultaneously, in which case the rear wheels may lock up when braking hard.
If the ABS warning light on the instrument panel comes on while driving, proceed as follows:
- Stop the car quickly, turn off the engine and start it again.
- Check battery voltage. If the voltage is less than 10.5 volts, charge the battery.
Attention: If the indicator lights up at the beginning of the trip and goes out after a while, this indicates that the battery voltage was initially insufficient, and then increased as a result of charging from the generator.
Check that the battery terminals are sufficiently tightened and that they have good contact.
Raise the car on the goats, remove the wheels. check the electrical wires of the wheel speed sensors for external damage (grinding). The rest of the ABS/EBV/ASR checks should be left to the workshop. The car electronics is equipped with a self-diagnostic system that remembers the trouble codes that have occurred. At the service station, these codes can be read and troubleshooted.
Attention: Before carrying out welding work using an electric welding machine, the plug connector of the ABS control unit must be disconnected (location: at the hydraulic block). Disconnect the plug only when the ignition is switched off. During painting work, the control unit may be exposed to a maximum temperature of +90°C.
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