DO I NEED DOOR COMPUTER?

You might need to diagnose the problem first, since the dealer seems (once again!) to have skipped that part. It's $15 to get to the repair manual at techinfo.toyota.com, but that's peanuts to make sure you know what's going on before tearing into the car.

I don't have a Gen 2 or the Gen 2 repair manuals, but I do have a paper copy of the Gen 2 New Car Features manual, which is the one that gives the important overview of what's where, doing what, and why. (You can find that also on techinfo, under the "NCF" tab.) The NCF section on "Theft Deterrent System" is probably the place to turn first, as it shows in just a few pages the relationship between the Body ECU (probably what the dealer was talking about, as if we should have to go around guessing what dealer techs are talking about when they don't use the correct terms...) and the inputs to it, and where these things are located.

It gets separate inputs from the (side) Door Courtesy Switches, the Back Door Courtesy Switch, the Engine Hood Courtesy Switch, the passenger, right rear, and left rear Door Position Switch(es) (I think those make a Wired-OR on one input), the (driver) Door Lock/Unlock Switch, and something called the Halfway Switch (in the picture, seems to be with the Key Slot in the dash). All of those could be worth testing, the old-fashioned way, with a multimeter.

The Body ECU can also give you diagnostic codes telling you what it thinks is going on. I don't know if this is true in Gen 2 still, but in Gen 1 the Body ECU could blink codes out for you on the DOOR light if you jumpered the Tc and CG pins. In fact, if it realized it couldn't communicate with the cluster to blink the DOOR light, it would blink the dome light instead. The repair manual will tell you if that still works. If they did away with that feature for Gen 2, then a Prius-capable code reader will be needed to get the codes.

Any dealer tech worth their exorbitant rate would have (used the correct names for the parts and) told you what codes they read out.

-Chap

 

Lots of people are using Techstream with various offshore "Mini VCI" clones. But seriously, spend the $15 and look at the repair manual; maybe it will turn out the Gen 2 body ECU can do blink codes the same way Gen 1 could. Then you don't need a tool at all.

Caveat: reading the codes only tells you what the ECU thinks the trouble is. That's usually related to what the trouble actually is, when you allow for the ECU being stuck in its box only looking at its inputs, and not able to climb around the car and check them like you can.

-Chap

 

Are lights on the button of the front door on? All the time? Only when that door is open? Not working at all?
Interior lights in door position. On all the time? Only when some door is open (delayed turn off)? Not working at all?
Trunk light in on position. On all the time? Only when trunk is open? Not working at all?

If it was the problem with some ECU it could be a problem with Combination meter or Body ECU. Combination meter is (somewhat) common failure item but not in this way. Normally ECUs are very rare to fail.

To scan a Prius best is to use Techstream software. You can get it cheap as Mini-VCI.

 

If you have the account, you're most of the way to the information you need, all that's left is learning your way around it. Once you're logged in, you should see some search boxes near the top for your car model and year, and below that, a bunch of tabs. One tab is RM (the Repair Manual), one is NCF (the New Car Features manual), and one is EWD (the electrical wiring diagram). There are some others too.

One thing I remember finding confusing at first was I would put in my search terms (model, year, maybe a keyword or two about what I was looking for), and down under my chosen tab would be kind of a flat unorganized list of matching sections from the manual. In other words, it's more like a search-engine result than a table of contents. The Aha! moment was when I realized I could just pick pretty much any of those, and it would jump me into that section of the manual, and there would be a proper table of contents on the left of that screen, which made more sense for browsing.

If I were you, I'd start in the Repair Manual at the Body Electrical section, and look for what it says about reading DTCs from the Body ECU. In particular, does it only describe using the Toyota scan tool, or does it also have a heading for "in case of not using Toyota scan tool" where it describes a jumper wire and blink codes?

I'd rather not have you compromise your account credentials by giving them to me (plus I'm kind of in the middle of some non-car projects), but I'd encourage you to go back and see if you can get the hang of finding the information that's in the manuals ... it will be a valuable skill for as long as you have the car.

-Chap

 

As the lights in bottom of front doors turn on and off when opening the door it means that body ECU does know if front doors are open or closed. And as the interior lights (in door position) stay on all the time Body ECU then has to think that a rear door or a hatch is open. I did not really understand how your luggage compartment light works. Does it (in ON position) turns off and on when opening and closing the hatch?

You can test the Luggage Compartment Courtesy SW and Door Courtesy SW on bough rear doors and you will likely find one that is broken. If those are all fine then it has to be wiring or (very unlikely) a bad Body ECU.