Oct 082019
 

Ford Focus

When driving in a bad snow storm should I leave the Positraction on full time or should I let the car turn it on when it is needed?



Your vehicle is not equipped with “Positraction” that I am aware of. Nor could I find any reference in the manuals. It may however be equipped with traction control. During the winter months and pretty much anytime you are driving leaving the traction control ON would be best.

What is Traction Control?

Traction Control monitors the speed of the vehicle and the speed of each wheel to determine if the tire is about to slip. It then applies the brakes with the use of the ABS system to prevent the tires from slipping. This can be benificial on wet and or icy roads.

Traction Control when turned off allows the tires to spin or slip. Say you want to spin your tires or hear them squeal, you will need to turn OFF the traction control.

ABS w/Traction Control & Stability Assist

The four wheel anti-lock brake system with traction control and stability assist consists of the following components: brake booster release switch, front and rear ABS sensors and sensor indicators, hydraulic control unit, stability assist event indicator, stability assist module, lateral accelerometer, steering wheel position sensor, transducers, trac control switch, yaw rate sensor and the yellow anti-lock brake warning indicator.

The stability assist system communicates with the PCM. The PCM assists with traction control by altering engine timing and fuel injector pulse. By altering engine timing and fuel injector pulse, the PCM can control torque, which in turn reduces excessive wheel spin. At speeds above 25 mph, traction control is controlled only by PCM command of engine torque output. At speeds up to 25 mph, the stability assist module requests the PCM to reduce engine torque while simultaneously applying and releasing appropriate brake to restore traction when one or both drive wheels lose traction and begin to spin.

The stability assist system continuously monitors vehicle motion relative to the driver’s intended course. The driver’s intended course is calculated by using sensors to compare steering inputs from driver with actual motion of the vehicle. The driver’s steering wheel input is measured from a steering wheel rotation sensor. Vehicle motion is determined using a yaw rate sensor which measures rotation about the vehicle axis, a lateral accelerometer which measures acceleration generated from the vehicle sliding sideways and wheel speed sensors which measure speed of each individual wheel. If there is a discrepancy between driver input and vehicle motion, the stability assist system changes the force at each tire to help control the vehicle.

Stability Assist System

The stability assist system defaults to on when the engine is started. Stability assist is not active when the vehicle is traveling in reverse, however ABS and traction control are still functional. System status is indicated in the stability assist warning lamp located in the stability assist/traction control switch. Stability assist is an independent function of ABS. The illumination of the stability assist/traction control switch indicates that the stability assist function is off and that ABS will continue to operate normally.

When the stability assist system is attempting to correct vehicle direction, the following normal conditions may be present: rumble or grinding sound; deceleration or reduction in acceleration of vehicle; ABS indicator may flash; vibration in brake pedal; brake pedal may move to apply higher brake forces accompanied by whoosh sound from beneath instrument panel. Also, the brake pedal may experience a slight movement when the system self-check is performed. The self-check is performed after the vehicle reaches a speed of 30 mph after 8 minutes of running time. Self-check will only be performed if the vehicle is stable, driver is not braking and accelerator pedal is depressed. If a failure is detected, the stability assist indicator will be illuminated. Anti-lock brake system will continue to function normally unless the yellow ABS warning indicator is illuminated. Normal brake function will continue to occur unless the red brake warning indicator is illuminated.

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