If you adjust the valve you must do a decal learn. On machine room inspection, set the car at the bottom with 30, 77n and 61u lit on the cpu. Go to 5-5 and set it to 1 and turn it to normal. The car will accelerate to full speed and then decelerate to a stop.......it will then go to the top, stop and do the same thing coming down. When the car comes back to the bottom floor, go to 6-20 and 6-21. This will tell you where the cpu is looking to see the slowdown magnets from the terminal floors.

If this distance is not set properly the 153 fault will keep happening. There is a center line on the floor flags that is your reference to the center of the magnet.