how do I wipe the error code so i can start the car

Unhooking the 12v will clear any codes that are not urgent, 10 seconds is a good time to unhook for, any codes appearing after a cold boot will be something to pay attention to

 

Most auto parts stores have inexpensive obd2 code readers that clear codes as well as read them.

 

For the Federally mandated, emissions codes. There are 3x Prius specific codes that an 'over-the-counter' OBD scanner will never read.

Bob Wilson

 

I suggest talking to someone with experience working on a 1998 JDM Prius. There are some owners in NZ and Australia that have these cars. I don't know of anyone in North America with a pre-2001 Prius. If the car has OBD2 port like 2001 and newer, check the OBD fuse(s) in the fusebox if a scanner won't communicate...blown fuse may make the scanner not "see" the car.

 

When attempting to restart the car after hooking the negative cable back up, what is the procedure, so that I don't get the triangle? It seems everything is out of whack when I do this.

 

When a code or warning comes back on, it means the problem is permanent. Now we can gain some insights if you slowly turn the key from position-to-position. But the 'ambiguity group' (the list of things that could be broken) remains too large to start 'swapping parts.'

You're really going to need a Prius-aware scanner. These scanners can get the error codes from the half-dozen control computers that operate the car.

Bob Wilson