got a serial number?
do you know what type of controller is fitted (sounds like a GE ev100)
code 16 is battery over voltage, which usually happens as your battery gets older and is about to crap out if it is a 36 volt, or if your running a 48 volt it can happen as your battery is realllllly dead when you turn on the key, either way you should get someone with an ev100 handset to set the voltage to what is the actual battery voltage and not the 36/48 volt default.
Code 29 is [more often than not] the traction contactors need to be replaced [it is probably worth it to replace the contactors as an assembly and be done with that for a while].