Having an issue with this unit. He is getting a fault 01 20 which says a “Start Sequence Error” along with a 01 87 & 01 88. The car abruptly stops in the hoistway and then levels into the closest floor. It is intermittent but increasing in frequency.

I have no additional information on the 01 20 fault. It is also intermittently throwing a 01 52 fault which is NTS stopping fault.

Appreciate any help on this.

Thanks

120 is a drive fault and should usually have a sub code by pressing select accept. What type of drive?
187 and 188 are almost always a brake switch that is bad or out of adjustment.