No Scan Tool Required For Brake Fluid or Inverter Coolant Changes

Discussion in 'Gen III Prius Care, Maintenance & Troubleshooting' started by The Critic, Nov 18, 2011.

  1. The Critic

    The Critic Resident Critic

    Oct 28, 2005
    Walnut Creek, CA
    2011 Prius
    I was looking through my copy of the factory service manual last night for instructions on how to do the brake fluid flush, engine and inverter coolant replacement, and the transaxle drain and refill.

    Although I never studied the Gen II's service manual, but based on what I heard about the Gen II and what I've read so far in the Gen III's service manual, I have concluded that the Gen III is far more friendly to do-it-yourselfers.

    Here's why:

    1) Brake flush.

    - The service manual starts off by stating that there are two ways to replace the brake fluid: with Techstream, and without. The method without techstream involves placing the car into ECB invalid mode. You are supposed to bleed the RF and LF calipers manually (in that order), though I assume that a pressure bleeder should be OK. For the rear, you hold down the pedal continuously (though not for more than 100 sec at a time) and the vacuum pump will push the fluid out of the calipers for you. The LR is done first, followed by the RR.

    2) Inverter Coolant Replacement

    - You do not need a techstream to activate the pump. Cycling the car on/off is adequate for bleeding the air out of the inverter pump. I know that people did this anyway for the Gen II, but on the Gen III, this procedure is officially endorsed by Toyota.

    I guess it is now easy enough to do all of the routine maintenance on this car by yourself. There is absolutely no need for a Techstream or high-level aftermarket scan tool for transaxle, coolant or brake fluid changes.
    frodoz737 likes this.
  2. Mendel Leisk

    Mendel Leisk Senior Member

    Oct 17, 2010
    Greater Vancouver, BC, Canada
    2010 Prius
    I've been reading through that a bit too. Could be it's a lot less daunting in practice than on "paper" (pdf paper). That "invalid" mode though: the car has to be in the mode "push the Power button twice without foot on the brake", I think. For the whole brake procedure.

    Then, when you shut the car off (which cancels the "invalid" mode), and then restart and depress the brake: is it going to detect something like transient low brake fluid pressure? And can you dismiss that without Techstream?

    Even if it is doable, I'm inclined to let the dealership take over for this sort of thing, just to play it cautious. Though it would be interesting to hear if someone went through a DIY, and how it went.
    frodoz737 likes this.