York treadmill t301 runs for exactly 20 mins and the E1 displays making motor cut out in this 20 mins keeping the speed at 10 the speed varies but clock stays the same ???

SOURCE: Proform Treadmill doesn't run constant speed.

You have a friction problem between your belt and deck. A treadmill of this age either came with a waxed deck, or requires periodic silicone lubricant spray on the deck. You can check your owners manual to see which type of surface your machine has. Typical belt life on a consumer grade treadmill is about 2 to 3 years. If you purchase a new belt from the manufacturer it will come pre-lubricated.

SOURCE: Treadmill runs then stops. E1 error and sometimes works fine.

Yes if speed sensor is too far from magnet it will not pick up belt movement. This confuses the computer and as a safety precaution it shuts the machine off. Find speed sensor and check for proper alighment with magnet.

SOURCE: york t101 treadmill ls error

York treadmill T101 will not run has a error L5

SOURCE: e1 error on york treadmill

You will need to check the speed sensor for proper alignment and function. it should be located near the front roller or mounted on the motor. It should be within a credit cards width of the magnet or toothed wheel. If properly adjusted check with an ammeter to see if it is opening and closing by manually spinning the front roller or motor flywheel. If it isn't replace the sensor. If it is functioning make sure you are getting 5vdc to it across the wires. If you are not replace the upper control board(console). If you are getting the proper voltage then replace the lower control board(motor controller).

SOURCE: E1 not ERR1 error appears on the display of

Your problem might be that a magnet has fallen off. Here's an illustrated guide that will make fixing it easy: http://fixmytreadmill.blogspot.com/2010/10/how-to-fix-treadmill-e1-error.html

Good luck.