Still P0401 after cleaning egr !! should we drive it?

I managed to undo the screws with a well sitting bit and a short ratchet.

And yes, it demands a reasonable hand strength rotating _and_ pushing the tool into the screw, but after an initial high torque application, it releases with a click and you can unscrew it with your fingers easily.

And you have to watch your tool to be perfectly aligned with the screw.

It really would be better, Toyota would use allen or torx screws here or maybe simple hex cap screw. But I understand, Toyota considers this valve as non serviceable, so no wonder, they do not care

Mat

 

it demands a reasonable hand strength rotating _and_ pushing the tool into the screw, but after an initial high torque application, it releases with a click and you can unscrew it with your fingers easily.[/QUOTE]

That's the exact kind of job the simple hand impact driver, bopped with an ordinary hammer, is made for.

Bop ... bop ... bop ... done.

 

That's the exact kind of job the simple hand impact driver, bopped with an ordinary hammer, is made for.

Bop ... bop ... bop ... done.[/QUOTE]

Added tip... a little dab of valve grinding (valve lapping) compound on the tip of the bit prevents camming out

 

*** Sorry folks! I had to split the post in a few parts, as it did not want to be posted as a whole ***

OK folks, I think, I have stuff to report (Prius from 2010, about 95000 km, about 60000 miles on it).

Warning - a long one

Today I was in my garage to see, if I can undo the two bolts holding the stator of my EGR valve motor.

The goal was to see, if I have to worry about the ramp failing.

If you have a good screwdriver bit and can place it properly into the bolt head, it is not that difficult to undo them.

In my case there was to little room to place the screwdriver properly on the left screw. A "PIPE, FUEL VAPOR FEED, 23818-37020" was too close to the stator body of the EGR valve motor. The bolt holding the pipe was too tight, I could not undo it, so I bent the pipe a little (very little) to the left.

 

*** Sorry folks! I had to split the post in a few parts, as it did not want to be posted as a whole ***

But I'm sure, it was a problem of my tool. If you have a normal long screwdriver, it will not be a problem.
I had to use something like this:


And, as I said, it was not that difficult to unscrew the screws.

I took the stator off, the rotor "unscrewed" itself a few rotations, as it was described here.

This is the best photo I'v managed to take of the inside of the rotor with the ramp:


So, as you can see, the ramp is in a good shape, no grease on the ramp itself, a very faint mark on the front of the ramp.

 

*** Sorry folks! I had to split the post in a few parts, as it did not want to be posted as a whole ***

But this was only the beginning of my journey today

After making photos I screwed the rotor back on, placed the stator back on it, bolted it down and... started the engine...

Result - very unstable RPMs in stage 0 - fluctuating very notably - never heard it this way

OK, I thought - I let it run a little - maybe it has to find the zero point again in the valve, but... no - it did not get better.
I switched the car off. Waited a little and switched it on again - again the fluctuating RPMs on idle.
Took the car to a short drive. Under load it seamed to work normally, but on idle - fluctuating RPMs.

After a little work of my few gray cells, I recalled, that I _did_not_ spun the rotor the whole way down until it clicks against the ramp, thinking, it would find its way down to closed position immediately after turning the car on... Apparently not the case.

Opened the valve again - it was an easy job this time - spun the rotor the whole way down, put the stator on it paying attention not to let it unwind again, bolted the stator down.

Started the engine... It worked smooth, as it always had!

So far so good.

 

*** Sorry folks! I had to split the post in a few parts, as it did not want to be posted as a whole ***

At some point I stood in front of my car with the hood opened and the engine running.
The engine stopped at some point and I heard two clicks coming apparently from the EGR valve...

I could repeat it and take a film of it:
lares.nazwa.pl/Pliki/20220915_131113.mp4
(I will delete this film from my server at some point, so it most probably will disappear from this place )

The engine started to work due to the battery SOC getting low and switched off, as soon as the SOC got to 50% (real 50%).

The clicks are at the end about 1'40''.

I would be VERY interested in hearing, if this is normal behaviour.
Could someone try to confirm (or not) this clicks at the engine shut down?
Please!

Additionally, as you can see on this film, the sound changes - the first time at 52'' and then at 1'32'' - it would be interesting if someone knew, what this sounds are.

And, as you can see, as my fingers begin to "dance" on the valve, the valve gets hot!
Hotter and hotter as you can imagine watching my fingers

So I got an additional idea of an eventual failing mechanism of the ramp...
If you have a partially restricted EGR cooler - not completely clogged - the exhaust gases are getting through the cooler, but are not really cooled down, as the engineers planed it.
The gases then have to go through the EGR valve and are very hot - much hotter, than the coolant.
The rotor gets very hot as well, so it can get softer, as any plastic would do, if it is getting too hot...

What do you think?

Mat

PS. My troubles posting this post where probably due to the link to the film... As I wrote it without the "h t t p s : / /" , it accepted it... Why is it like this?

 

The change at 1'32" is easy: the battery SoC has become acceptable, so the generator load is removed, and the engine transitions to idle.

Up until that point, the engine has been charging the battery, running at near-idle RPM, but noticeably higher load and throttle opening.

The change at 52" is something more subtle. It's a change in the whine made by something under pulse-width modulation. Normally the most noticeable PWM noise under the hood is the one from the throttle body. The engine may have warmed up to the point where a small change in throttle opening was called for. That might be easiest to confirm with a mechanics' stethoscope on the throttle body.

I'm not sure that I heard something I would call a click, but I did hear something that might have been a very brief change in the PWM of something, sort of like a quick buzzy beep. That might have been another quick tweak of throttle position, just before stopping the engine. With your fingers on the valve, did you feel it from there?

That is probably a giveaway that the engine is operating under load during the first 1'42" or so of the video, for charging the battery. At true idle, the EGR valve should be closed, and with no gas flowing, it should not be getting hot. But under moderate loads, as when charging the battery, some EGR will be in use.

This is all a little unexpected. There's no simple way to reassemble the valve without ever letting the rotor unwind again; you can hold on as long as you can while replacing the stator, but eventually you need your fingers out of the way, and the rotor winds back upward a little bit. That leaves the valve slightly open when you bolt the stator fully down. But that normally should not be a problem, as, just as you thought, it is supposed to find the closed position whenever at idle.

But here again, it may make a difference whether the engine is really idling, or is under battery-charging load. Under load, the valve will not be driven toward the closed position; the ECM will want it partly open.

You can get a genuine idle by shifting to Neutral. (To keep that from simply stopping the engine, you can be in maintenance mode.)

The valve position is dead-reckoned; there isn't a sensor for it, but if the ECM thinks it is starting from closed position, it will count off so many steps toward open. If it was already partly open, it could end up too far open.

But I am surprised it did not drive the valve to fully closed just as the engine was starting.

According to the waveform info in the repair manual, the strategy is to simply never stop sending pulses in the closing direction, whenever the engine is idling. So at idle the valve is always trying to close further, blocked only by the ramp/stop. That should be a fairly reliable way to find the closed position, whenever the engine is at true idle for a couple seconds or more.



The pulse sequence shown at the left will drive the stepper motor toward the valve-closed position, and the stated condition says the sequence should be seen whenever the engine is idling and warmed up.

I wonder if that means no EGR signal is sent when the engine is cold? And therefore, if you happen to have disassembled the valve and it is a bit open, it won't find fully closed until the engine is fully warm and truly idling? That sounds like a bit of silliness on somebody's part, though probably never an issue unless someone has just had the valve apart.

If that's the case, maybe a good strategy for doing a ski-jump check is to warm up the engine first, then do the check quickly, reassemble, and restart the engine while still mostly warm, so it will quickly be at operating temperature and not have to go through a whole warm-up with too much EGR.

Can you check your ECM calibration ID? There was a firmware update available as part of an EGR TSB. Nobody really knows what they changed. If they had noticed mashed-ski-jump syndrome, maybe somebody asked, "why do we pulse toward closed unceasingly whenever the engine idles? The valve has a 110-step range. What if, when we want to close it, we just send, say, 200 pulses in the close direction, and call that good, and stop sending pulses? That way we wouldn't be holding the stop under pressure against the hot metal all the time!"

If you had a 'scope to hook up to your EGR leads, it might be interesting to see exactly when it is being sent which sequences of pulses.

160 MB was quite a lot to have to download just to listen to less than two minutes of a car noise. It might be a better use of space/bandwidth to downscale and/or compress the video before uploading, so that it's still decent quality for the purpose but more resource-friendly. And with a much smaller file, maybe you could afford to keep it around longer.

 

The clicks extracted:
lares.nazwa.pl/Pliki/20220915_131113_clicking_sound_extracted.wav

The clicks extracted, slowed down and amplified:
20220915_131113_clicking_sound_extracted_and_slowed_down_amplified.wav

And yes, I think, I have felt something at my fingers (besides of burning ).

Mat

 

Ok, I confess, those are clicks.

It might be nice to have a video of that, also showing a 'scope on the EGR leads.

Or, disconnect the EGR connector just shortly before when you expect those clicks, and see if they still happen.

Or both....

 

My ICE was cold soaked - standing in the garage over night. So starting it would demand the EGR open? It is then in the so called in Germany "Flammenwerfermodus" - "flamethrower mode". Is here the EGR opened?

Yep. Could be a good advice, if we can confirm, that in S0 the EGR wants to be opened.

I could read the calibration IDs, but I'm afraid, not now - it is night down here

Your explanation of a possible improvement is good - worth of an update

I do not have a scope...

And yes, I read your another post, where you showed the EGR motor signal, and I was sure, it will find the zero position with no hesitation

Mat

 

I don't have a scope

The idea with the connector is not bad - one could actually know, when the ICE is about to shut down...

Mat

 

If I click on the link, it opens a new tab in the browser and shows me the video - no need to download.

I'm not planning to remove it tomorrow It will stay there at least for a year

Mat

 

I think, I can give you the calibration ID - but which one?

Calibration ID - $7E0
Calibration ID - $7E0
Calibration ID - $7E2
Calibration ID - $7E2
Calibration ID - $7E2
Calibration ID - $7E2
Calibration Verification Number - $7E0
Calibration Verification Number - $7E0
Calibration Verification Number - $7E2
Calibration Verification Number - $7E2
Calibration Verification Number - $7E2
Calibration Verification Number - $7E2

What are they, and why I do have so many?

Mat

 

That's your web browser being clever, and hiding from you some of the details going on behind the scenes. It is playing the file while downloading, and not saving it anywhere.

For some of us, with slower connections, the playing has to pause for around two seconds out of every three, because of the high bitrate of the video. If it were downscaled, saved at a higher compression level, or both, that wouldn't happen. As it is, to avoid the annoying pauses, I have to download it first, then play it.

And some web browsers have further annoying features. Because your link did not include the https://, my version of Firefox will refuse to download it (it's "insecure"!) ... but will be happy to play it in-browser (pausing every 3 seconds to rebuffer). I can paste the link into the URL bar and add https:// in front, but then the browser will only play it (with rebuffering) and offer no download option. (I wish the firefox "this download is insecure" dialog would just have an "ok, try the same URL but with https" button, but it doesn't.)

PriusChat has a "Media" area, where it seems videos are not enabled at the moment. It seems the concern was about storage space. I've suggested enabling it, only with a strict limit on file size, one that would force thinking about the scaling and compression of videos being uploaded; that could be a useful feature for PriusChat to have.

 

I don't think it does want to be opened. Only the description in the manual says the "force to close" pulse sequence is sent when "idling with warm engine", which could possibly mean that simply no pulses are sent at all with cold engine. That would leave the valve exactly as it was before, which would normally be closed already, except in the rare case that someone has recently taken it apart.

Or the condition in the manual might simply be misstated. A 'scope could answer the question quickly.

 

I will consider to scale down the video and reupload. And try to keep the audio untoutched.

I regretely do not have a scope, so it is not an option for me...

Could you point out which calibration ID is the right one here?

Are you driving a 2010 Prius? Couldd you try to confirm the clicks on ICE shut down?
If your is not clicking, it could mean, I did something wrong on reassembly of the valve...

Mat

 

There are so many because there are several ECUs in the car that have at least one each (though there are also some ECUs that don't have visible calibration IDs). I don't know them by their hexadecimal addresses, because Techstream simply shows them next to the corresponding ECU in health check results. No need to memorize hex numbers.

I can say that in the US, the TSB about the EGR update (T-SB-0027-16) gives 34715700 or higher as the desired ECM calibration after update. My 2010 came with calibration 34715200. You might see if any of the IDs you see resemble those.

But I have the impression you're not in the US market, and the calibration IDs for your area might be different. There may be another TSB for your area that gives a different version to update to.

There may be some time for me to do that, but perhaps not right away. I wouldn't worry too much about misassembly ... the valve is simple enough I don't think that's very likely.

 

I tried to link the video _with_ h t t p s : / /, but PriusChat refused to accept the whole post, if I let it stay in the link...
Maybe I'm doing something wrong, am I?

Mat

PS. It is doing it even now! I have to place spaces into the h t t p s : / /
Otherwise I get an error:
"Oops, something went wrong.
We could not find the page you were looking for. But, maybe we can help.

Navigate through our top menu or contact our team, browse the forums or search for the keywords, to find what you were looking for. Or, start a new discussion by clicking on new thread, and open the conversation "

 

Im writing from Poland.

I simply give you all I have:
Calibration ID - $7E0 34717200
Calibration ID - $7E0 A4701000
Calibration ID - $7E2 896B34750000
Calibration ID - $7E2 896B54701100
Calibration ID - $7E2 898844701400
Calibration ID - $7E2 898844702300

I hope I did it right
It would be silly to damage something out of plain curiosity or wanting to check and to show others, how an intact ramp looks like
I would be very thankful, If you could here to the clicks on your Prius!

Mat