Another EGR thread

1. Press Start button 2 times without Brake
(ignition On)

2. Press Gas Pedal 2 times

3. Press brake and shift to Neutral

4. Press Gas Pedal 2 times

5. Press Park

6. Press Gas Pedal 2 times
(hybrid warning light will start flashing)

7. Press Brake and Start button
(starts engine, shutdown returns to normal)


Cliff Notes:

Ignition Mode, 2Gas, Neutral, 2Gas, Park, 2Gas, Start Engine

 

Those spark plugs were ugly

 

Google Amayama Aisin wpt-190

 

It’s 2, not 3? Repair manual inspection modes saying 3.

I did this, fall before last, but can’t remember. Could verify with the @NutzAboutBolts video

addendum: @NutzAboutBolts says 2.

Google AI summary:


How to Enter Toyota Inspection Mode (General Procedure)
This procedure must typically be completed within 60 seconds while the vehicle is parked.

1. Start with the car OFF (or in OFF mode).
2. Press the POWER button twice without touching the brake pedal to enter the ON/IG-ON position.
3. Fully depress the accelerator pedal twice.
4. Depress the brake pedal and shift into Neutral (N).
5. Fully depress the accelerator pedal twice.
6. Shift into Park (P).
7. Fully depress the accelerator pedal twice.
8. The dashboard should display a "Maintenance Mode" message or a flashing hazard light (car with exclamation point).
9. Depress the brake pedal and push the POWER button to start the engine, which will now run continuously

 

Generally overseas sellers don't want them back. Was the ebay pump $115 including the thermostat?

Counterfeits can look very good these days. The front pic you posted looks exact, however the prior "genuine" direct Aisin units had the Toyota logo ground off.




There are aftermarket units that make no bones about being copies. This brand also makes an egr valve with known different internals.

 

Amayama's been reliable for me.

I was replacing an oven control board and touch screen once: the replacement board was good, but it's touch screen was defective. Contacted seller (North American) with pictures/info, they phoned up and just issued a full refund. Ultimately I peeled the functioning touchscreen off the old board, transferred it over, a little beat up but it all worked.

 

The pic with the ground off Toyota logo was Aisin. Lots of good long term reports on that one. Not so good on other counterfeits.

You won't find Toyota parts with QR codes, barcodes or serial numbers.

Here is the thing:

Most of us like reliability and buy critical parts like this from Toyota. Most aftermarket parts for Toyota are not as good by a large measure.

I would buy from a Toyota dealer online. Current April 8, 2026 total price $191.



If I was a newbee and already put on a free clone, I would leave it on until my new one showed up. You really need to determine if the parts cannon you already fired solves your issue.

Toyota electric water pumps last a long time with proper coolant changes. I have over 300k miles on mine. Ten coolant changes, 5k oil changes and two egr "cleanings".

I monitor my coolant temperature because the factory, no audible, dash light may be missed and has been reported to blink on and off once if coolant has been lost.

I use an audible alarm at 220f so I don't have to watch it. My wife normally drives the car and would hear it before it reaches 248f (the normal warning temp with no pump codes). Then I would hear about it one minute later.


P10 Obd2 Display ~$30

Just having it for years allows me to know normal. In Central Texas at highway speeds normal is about 195f. Worse case up a very steep hill for a half mile its 204f and falls back in seconds when back to level.

There is no guessing. Have not needed it yet.

 

Three is certification mode which is pointed out in the manual.

 

@NutzAboutBolts went with the Aisin. Aisin makes the ones with additional Toyota emblem. Next coolant change (at the 20 year mark with our 2010) I might replace the pump and thermostat, and when I can get this on my doorstep for about $143 CDN (~$103 USD), I'll give it a go.

I think you're right, there's one that says two, and the following says three. The repair manual formatting is very confusing though, hard to tell which is which.

 

Earlier generations had just one inspection mode, which combined the effect of keeping the engine running (for purposes like emission testing and adjustments) and inhibiting traction control (for purposes like dyno testing).

Gen 3 split that into two modes, "maintenance mode" (like the old mode), and "certification mode" (only inhibits traction control). Maybe not a perfectly clean split, as the summary chart on the first page for the procedure makes it look like "maintenance mode" still does both of the old things.

Anyway, "maintenance mode" is the two-stomp mode, and "certification mode" is the three-stomp mode.

 

Part of the problem is understanding the purpose of the two modes and then choosing the right one. In the referenced pdf it is not clear Maintenance Mode can be used to warm up the engine with a constant idle.

The condensed version is also confusing about shifting to and from Park and Neutral before or during the gas pedal operations.



And then the critical sixth step is on the next page. So we have the procedure at least times in this thread alone but one is wrong. Best two out of three?

In reality I find it quicker by far to simply drive the car for 5 minutes and allow the thermostat to open. You then have accurate level verification and know you have water pump operation.

 

I'm not sure which was the "referenced pdf" or the "condensed version" ... I guess this is a thread long enough that a few different posts had attachments. The PDF that Mendel attached in #77 seems to include the chart that explains the maintenance mode/certification mode differences, and it doesn't seem to have the sixth step after a page break ... though, in general, it is pretty common for PDFs made using print-to-file from Toyota's online manuals to have awkward page breaks and important stuff split across the break. Have to remember to flip the page and check.

 

Jumping in late here and after a hitatus. I had a small, but noticeable due to startup shake, Head gasket leak, which I ultimately repaired myself after denial lol.

Coolant loss was minimal but enough from time to time to get it to rattle. Anyway, I do not recall cylinder 1 being all that clean, I'll see if i have photos. I see you are in Jacksonville, NC. There is a shop specializing in Prius Head gasket near me in Western NC very reasonable (Reminded me of Gasket Masters).