Just diagnosed the same issue on our 1003 and fixed it.
Started like this after about 2 years in saltwater
environment
Error 33 - wiggle the cable from
motor to battery at the battery connector or disconnect and reconnect. that made it
work for a while.
Then I had to clean the contacts with contact spray to make it work. Apparently Torqueedo recommends WD40 for protection the contacts. I have not tried that yet.
Then - We could not make the Error 33 go way anymore. I checked the contacts under a magnifying glass and cleaned as much as I could with a dentist tool. No luck.
Because we wiggled the plug so often, I suspected we may have broken a cable. I checked the conductivity from the plug pins directly to the motor - that was fine.
So finally I took a small drill bit between my fingers (no
power tool) and drilled away the front area on the plug plastic at the battery connector to the motor. There are 4 large battery contacts and 4 small
communications contacts. The small ones were giving the problems.
After finger-drilling away the plastic at the small contacts, I took a small dentist tool (a small sewing needs will work too) and gently but firmly press it between the plastic and the tube-shaped contact metal to bend it slightly inwards.
Reassemble and test - Damn ERROR 42 - Wrong battery voltage. Measured everything, even each cell level voltage on the board at the balancing resistors. All was fine. Then on another forum I found one person who had traced this error to blown
fuses. There are two 25A automotive-style (but 80V) blade
fuses on the battery circuit board. Yep - they were blown. I don't remember shorting anything, but what the heck. I tried standard 15A (that is all I had) automotive 12V fuses.
And all is fine. Just have to get the proper 25A fuses now. I will stay with the 12V ones for now, as I am away from good supplies.