Been lucky enough not to get error codes on my Gen I, but upon reading these posts, I hear that to clear some "error" codes you disconnect battery. Instead of that hassle, can you just unplug the DOME fuse located in the engine compartment, or does this just cancel the assessories, and not the codes? If not, what is a good brand of battery disconnect switch (the kind you just twist a knob to kill power completely) Just saw cheap brass ones with green knob that won't work on the Prii. Suggestions would help
Disconnect the ground wire of the battery located in the trunk on the left-hand side. Leave the B+ terminal alone. This is fairly easy although you may have to pull the felt cover around the metal rim to reach it easily. The "DOME fuse" has no effect because none of the half-dozen, control computers are on that circuit. Each control computer has their own, DC power source and their fuses are located on at least three different fuse boxes. Failing to get any one of them simply preserves any codes they may have already recorded. If pulling the battery ground wire is too hard, you could get a Prius friendly scanner and command clearing the codes via the OBD interface. This is not a single wire but a complex, software protocol. Bob Wilson
I own and use: ScanGauge II ($100-150) - displays four active fields from over 20 fields. Has an XGAUGE programming option so you can add OBD codes specific to your model Prius (or other vehicles.) XGAUGEs to read traction battery and other details are available on the net. Weakness: ISO-9141 interface works best with a 'pig tail' to avoid false error spikes during auto-discovery, and no data recording capability. AutoEnginuity ($500+your Windows laptop) - full-up diagnostic system similar to Toyotas TechStream Lite. Can record data for later analysis. Weakness: tends to work with just one ECU at a time so combinational metrics for engineering studies are difficult. Graham Minisanner (only used) - these rare scanners have ~50, preprogrammed metric and the ability to view engine, hybrid, and battery ECU codes. It has a data recording port. Weakness: no longer in production, no expansion capability. The OBD scanner field changes and there are open source efforts. So this is not the definitive list. Just make sure it has an ISO-9141/KWP2000 capabity . . . and a return policy. Many OBD scanners promise much and don't deliver in pratice. Bob Wilson
