GrahamC230K
MB Enthusiast
- Joined
- Jul 14, 2002
- Messages
- 9,755
- Car
- Audi A3 & S4 quattro
Got a few questions about ASR.
Hard to search on this topic as most forums only allow 4 character words minimum to search on!
My understaning of ASR is that when wheel spin is detected it brakes the offending wheel and also cuts engine torque. Triangle in middle of speedo flashes. This is quite evident by a simple test if nothing else!
Now with the ASR switched "off", the triangle illuminates and does the same thing but ONLY brakes the rear wheels, does not affect engine power. This too I know to be true, the benefit of having squeeky rear brakes when hot - I can make mine squeek by booting it in 1st!
So all this thinking came about when my car was on a rolling road with a strap down system designed for no wheelspin on cars with far more power than mine but with my car, the ASR "off" the triangle fashed away the WHOLE time.
1. Did the car know the front wheels were not oving and hence assumed a traction problem?
I thought only ESR equiped car had sensors on the front wheels. But maybe ASR uses the front wheel ABS sensors to.
2. In a thread on benzsport this got posted by someone in the US from their owners manual:
This is interesting.
I know the light certainly comes on at any speed (have had mine activate going over hump back bridges at 80mph), but does it stop activating over 50Mph?
It seems this is the case on US market cars, but is it true in the UK (I know the do differ some times)?
I have checked the "Driving" section of my handbook and no such detail, but I am missing the "Interior" section, which may detail the operation of the indicator light.
Can someone check please?
thanks.
Hard to search on this topic as most forums only allow 4 character words minimum to search on!
My understaning of ASR is that when wheel spin is detected it brakes the offending wheel and also cuts engine torque. Triangle in middle of speedo flashes. This is quite evident by a simple test if nothing else!
Now with the ASR switched "off", the triangle illuminates and does the same thing but ONLY brakes the rear wheels, does not affect engine power. This too I know to be true, the benefit of having squeeky rear brakes when hot - I can make mine squeek by booting it in 1st!
So all this thinking came about when my car was on a rolling road with a strap down system designed for no wheelspin on cars with far more power than mine but with my car, the ASR "off" the triangle fashed away the WHOLE time.
1. Did the car know the front wheels were not oving and hence assumed a traction problem?
I thought only ESR equiped car had sensors on the front wheels. But maybe ASR uses the front wheel ABS sensors to.
2. In a thread on benzsport this got posted by someone in the US from their owners manual:
If one drive wheel loses traction and begins to spin, the brake is applied until the wheel regains sufficient traction. The traction control engages at vehicle speeds up to approximately 25 mph (40 km/h), and switches off when traction is regained, up to 50 mph (80km/h).
The ARS warning lamp, located in the speedometer dial, starts to flash at ANY vehicle speed as soon as the tires lose traction and the wheels begin to spin.
This is interesting.
I know the light certainly comes on at any speed (have had mine activate going over hump back bridges at 80mph), but does it stop activating over 50Mph?
It seems this is the case on US market cars, but is it true in the UK (I know the do differ some times)?
I have checked the "Driving" section of my handbook and no such detail, but I am missing the "Interior" section, which may detail the operation of the indicator light.
Can someone check please?
thanks.
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