Gen3 modes: Ready, Limp, Maintenance, etc.

Chap just summed up the degrees of on-ness eariler today. IIRC, they're:

AUX (one push of start button): just the radio woke up
ON (two pushes of start button): mostly woke up, except no engine running
READY (one push of start button, with foot on brake): engine starts/stops, typical driving condition

There's several "maintenance" modes. For various, pretty esoteric maintenance requirements. For example, keeping the engine running constantly, after coolant change. "Invalid" mode is for doing some brake work, brake fluid replacement mainly.

 

Maintenance Mode
Continuously Idle Engine

Press Start button 2 times
Press Gas Pedal 2 times
Press brake and shift to Neutral
Press Gas Pedal 2 times
Press Park
Press Gas Pedal 2 times (hybrid warning light will start flashing)
Press Brake and Start button (starts engine, don't drive it, shutdown to return to normal)


Invalid Mode
Useful for normal brake flush without Techstream Scanner

Press Parking Brake
Press Start Button twice
Press Brake Pedal and shift into Neutral
Press Brake x8 in 5 secs
Press Park
Press Brake x8 in 5 secs and release
Press Brake pedal and shift to Neutral
Press Brake x8 in 5 secs
Press Park (Blinking brake light)

You are in Invalid Mode

Bleed rear brakes by holding pedal down
Bleed front brakes by pumping brakes
Power down to exit invalid mode

Consider using charger on 12v battery during process

 

There’s a couple of specific gotchas:

1. when shifting out of park, you need to depress brake pedal. You do this normally, but perhaps without thinking. Repair Manual description of the modes does not note this. (@rjparker does note it, in his post.)

2. Invalid Mode requires car to have parking brake applied. It’s mentioned at the outset of Repair Manual description, but not noted/stressed.

 

It's good to be clear this isn't a complete bleed procedure. It works if you are simply flushing fluid (new fluid in, old fluid out, no air). It also works if there is only air down at the wheel ends of the lines, as when you've just replaced a caliper, say.

If there's any air that got into the head-end units, you need the actual bleed procedure invoked with Techstream to work all of those valves and get all the air out. Invalid Mode keeps the brake ECU from yelling at you while you mess with the brakes, but it doesn't do the active stuff a full brake bleed needs.

 

Primarily need Techstream for a brake booster (master cylinder and or brake pump) replacement. Invalid mode is not some kind of hack, it is a Toyota recommended normal brake flush procedure.

There are aftermarket scanners that can do the more involved brake booster replacement flush and calibration. XTool is one and they offer a bluetooth version that uses your phone or tablet. Plus it is good for other manufacturer's vehicles besides Toyota. However most of the advanced diyers here use the hacked Techstream software for a PC along with a specific hardwired interface. Illegal but cheap.

 

I think the usual ploy with Techstream is to get a clunker laptop, if that's possible. It used to work better with an older Windows OS, say Win95, though that may not be a factor now?

 

Yes, exactly: it is a Toyota recommended normal brake flush procedure, and flush is what you're doing when new fluid goes in, old fluid comes out, and no air is there. Invalid mode works for that, and is fully documented for that purpose in the manual.

It also works when the only air is way down at the wheel ends of the lines. You can get away with it then too.

What it does not work for is when there's air in the head-end components, and it doesn't appear in the manual for that purpose.

When you need the procedure for bleeding air out of those components, you don't necessarily need Techstream. Techstream is not what knows the procedure; the procedure is baked into the brake ECU. You just need any scan tool able to send the brake ECU the command to do it. Techstream can do that, of course, but isn't the only option.

This thread comparing other OBD-II tools and their capabilities can give you some ideas. It's in the Gen 2 forum because mr_guy_mann has been testing on Gen 2s specifically, but the most promising products there are probably also promising for Gen 3.

 

Several have reported no success with vms. Part of the Techstream hack version is some registry modifications to make it work. Most people have done it with xp or win7 running xp mode.

Buying a used brake booster can be tricky as there are different versions by tire size, Prius model and year. When you buy a new set you will get the right parts based on your vin.

 

This worked for me and still does—but I used software directly from Toyota and Drew Technologies, which I realize may not fit every budget.

The current, supported products are fully compatible with 64-bit Windows operating systems.

I don’t know what one might expect with unofficial copies of the Techstream software, nor with the device drivers or J2534 pass-through libraries for inexpensive vehicle interface modules, whose sellers, having copied the software that came with whatever device they cloned, may lack the ability to update it.