ODB reader

OBD - On-Board Diagnostics. The original OBD was manufacturer specific. OBD-2 standardized the connector and provided some common functions.

For the most basic stuff, a generic Bluetooth ELM327 compatible dongle and a smartphone with any one of a dozen free downloadable OBD2 apps. You can find those on Amazon or eBay for less than $10, but it's best to look through the notes for the smartphone app you want to use. Some of the cheapest dongles only offer the bare minimum compatibility.

I've got Piston, Car Scanner, ScanMaster, MotorData OBD, and Dr. Prius. MotorData OBD seems to be the most complete (more later) I've also got an Android phone. Over the years, I've downloaded the second, third... app when there's been something I've needed to do, but couldn't at the time.

What works for me, may not work for you. You may have an Apple phone. There may be other issues too. I started out a sub $10 dongles off of eBay. It worked, so I got more and put one in the glove compartment of each car. I also got a VLinker MC, which seems to work a little faster, is more compatible, and was on the list of one of the apps I was trying to use. It works slightly better for me, but my wife's phone won't even link up with it (but will with the sub $10 ones). She has the same model phone, and we got them both at the same time. All I can figure is that she's linked her phone with some other Bluetooth accessory that's incompatible with the VLinker and her phone is trying to use the Bluetooth dongle as a smartwatch or something like that. Her phone can link with the sub $10 dongles.

You'll probably be disappointed at some point because, for the most part, those apps only talk to the engine's Electronic Control Unit (ECU).

It's a common misconception that with the OBD2 reader, you're communicating with the car's controller. The days are long gone when there's only the engine ECU. There is a network of a couple dozen linked ECUs all working in unison. These controllers all live on the CANBUS (two of the pins on the OBD port are the network connectors). CANBUS is getting a little old, so it will probably get phased out if it already hasn't been.

Some of those free apps, now want you to buy upgrades to allow you to talk to the other controllers on the bus, others won't talk to the other controllers at all. Some apps only provide generic OBD2 functions, others provide access to Toyota specific functions, and there are also hybrid specific functions too. Reading through the threads, as it appears you have done, you'll see a lot of problems where people get a warning or failure light and there's no code, because their reader only grabs the generic codes out of the ECU. It looks like the MotorData OBD has a lot more Toyota specific functions, and other controller functions that you can purchase as add-ons. Some with a short term subscription that's relatively inexpensive for getting you through a problem, more expensive if you want to keep using it after a few days.

Clearing the Engine ECU codes is part of the generic OBD2. Access to anything further is a hit or miss proposition. Like accessing to the other controllers. App developers start with the basic, but they don't have the resources to program in all the different car make, model, and year specific functions, and all the different controller's specific functions.

Then there are the functions. Clearing codes is one thing, bi-directional control allows you to turn on relays, and turn on and off things (like you would need to bleed the brakes). At that point, you'll probably want something with a more robust link. Bluetooth gets slow and sketchy when you want to do bi-directional control. I keep eying the XTool D7, but I just can't justify the $300+.

Techstream seems to be the gold standard for doing everything.

 

Take a look at this thread. I would guess that some of them would work on a Gen 5. https://priuschat.com/index.php?posts/3290690

The Autel AP200 is a good choice and costs about $60 on Amazon.

 

To avoid confusion for others that are reading this thread:

ECU is an abbreviation for electronic control unit. There are over a dozen ECUs in a Prius. One of them is referred to as the engine ECU or engine control module which is abbreviated as ECM, that is the one you are referring to in the quote I copied.

 

Corrected... My bad.

 

On top of that, the actual network topology has tended to be pretty weird. In a gen 3, you can't say "the CANBUS" 'cause there's more than one. Some ECUs connect to more than one, and a scan tool can communicate with others by asking one of those to relay messages there and back. The car also has LIN and AVC-LAN buses and some ECUs that still respond to jumpering certain wires at the diagnostic connector to ground. Gen 2 had BEAN and some CAN and some of those other networks, and gen 1 had no CAN, but some BEAN, and some ECUs that communicated on the K-line but at different bit rates, so a scan tool could talk to one or the other but only by changing its UART settings in between. I haven't even tried to look up the fun details for gen 4 or 5.

That's part of why there are so many generic scan tools that just don't know any of the voodoo they'd need to use to learn everything from the car.

 

At this point Techstream as we know it has to settle for the Silver Medal as Toyota now recommends their newer GTS+ software which is browser based and specifically locked down against hacked versions.



A member was recently trying to flash his ecm with a legal Techstream and was instructed by Toyota support only GTS+ would work. He paid $70 for 2 days of Professional access (required for scantool function), downloaded GTS+, went through a learning curve with the newer Toyota software and got his ecm flashed.