This may be a long shot but last year I had a very similar problem. Code 23 and 24 intermittently at first then happening every time.

The problem turned out to be a faulty accelerator micro switch. (1MS I think) It clicked solidly and I think I had already checked it with a meter. The voltage was very close to battery volts but there ended up being a 3 or 4 volt drop across the switch. This would have been enough to pull in a contactor on many systems but the EV100 picked it up as a fault and coded 23/24.

Good luck with it.