i have an abs problem the brake pedal is very hard when i push it and the car will not stop the servo mecanism its ok its look like the engine is stop is the same senzation when i push the brake i forget to tell you when i pull out the fuse of the ABS the brake its fine but no ABS ENY IDEA????????
Hi Mosr, may be it is an problem with one of your ABS sensors. I have the same failure with my old Audi80, when i push the abs-out-button the brake works normal again but with no abs. If you have the possibility, check out the failure codes. If you can't find any failures, try to measure each sensor with an oscilloscope. But the car in the air, unplug the sensor and try to measure the sensor while you turn the wheel. if any one of the pictures on the oscilloscope are different, you got the damaged sensor. I hope i could help you a little bit Nice wishes Martin
Problems with your voltage? ABS consumes a lot of power, probably your ignition system fails due to power drain caused by the ABS (ECU). Measure your onboard voltage during a brake manouver.
dear mosr, i think one of connection to sensor is not good.coz this happened with me couple of years back when i took my car to Audi workshop to check my brakes after that it started and every time i had to switch off the ABS from button.chk the sensor connection.
ENY IDEA???????? 
