Hi,
Roughly speaking;
ASR: Anti Slip Regulation
Fitted to Golf MK4s upto end of 1H 2002
Is a form of traction control system (TCS), that uses the ABS sensors and ABS controller to limit wheel slip when power isn't being transmitted to the road, and as such isn't hugely intelligent.
The ABS/ASR controller continually monitors all 4 wheel speeds (using the ABS/wheel speed sensors {G44, G45, G46, G47}), and applies braking pressure through the ABS pump/hydraulic controller to any wheels that are spinning comparatively too quickly.
ESP: Electronic Stability Programme
Fitted to Golf MK4s 2H 2002 onwards
ESP was developed jointly by Mercedes and Bosch, and is an enhancement/combination of ABS, ASR, EBD and EDL.
This enhances ASR, and adds 'smart steering' as well as traction control. Essentially ESP has 3 extra sensors, that ASR doesn't;
- Steering angle sensor (mounted at the steering wheel): G85 (optical)
- Lateral accelerations sensor: G200 (magnetic hall effect)
- Yaw/rotation sensor:G202 (piezeoelectric)
Like ASR, the controller is the ABS hydraulic controller, that can apply braking pressure to indivudual wheels.
ESP tries to form a type of closed loop steering control system, with demand taken from the Steering angle sensor, and output measured mainly using Yaw sensor, but also assisted by the Lateral acceleration and ABS/wheel speed sensors.
This is 'smart steering' since, ESP will try and match what the driver wants to do (steering wheel), against what the road won't necessarily allow (i.e. due to ice, snow, grit ...). It also tries to compensate for oversteer, understeer and sudden/jerky steering.
In short, ESP tries to prevent the car from skidding,
(sliding and spinning ?), so could greatly reduce the chance of an accident.
However, it can't turn an unsafe/wreckless driver into a safe driver.
Regards,
TR7
