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  #1  
Old 08-26-2013, 05:54 PM
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Default Toyota EVAP Testing....Pulling my hair out

Okay guys, so I'm going to to post all 11 steps of the Snap On Functional Testing on a 2001 Toyota Camry. A little history on this car before we get too deep into the JPEG's. First, we replaced a Charcoal Cantister with switching valve that is placed on the canister 3 years ago. Customer came back last month, proceeded to smoke test to find a bad gas cap. Did a vacuum test while cycling solenoid(per Toyota testing procedures) On the Canister Closed Valve (mounted on airbox), and also on the Purge Valve. Neither of these failed during test, held vacuum and cycled properly over a dozen times each. So, after cap, vehicle came back last week. Smoke test again, found nothing, but then started to test Switching Valve mounted on Charcoal Canister. Noticed slight vacuum leak while cycling valve open and closed, so we replaced another Charcoal Canister w/Switching Valve. I proceeded to run the 11 Step test, and here's my results:
Gut Feeling says this will be back...
Attached Images
File Type: jpg ToyStep00.JPG (80.5 KB, 210 views)
File Type: jpg ToyStep01.JPG (94.9 KB, 197 views)
File Type: jpg ToyStep02.JPG (95.7 KB, 193 views)
File Type: jpg ToyStep03.JPG (94.8 KB, 187 views)
File Type: jpg ToyStep04.JPG (93.7 KB, 188 views)
File Type: jpg ToyStep05.JPG (94.8 KB, 186 views)
File Type: jpg ToyStep06.JPG (94.1 KB, 187 views)
File Type: jpg ToyStep07.JPG (94.7 KB, 186 views)
File Type: jpg ToyStep08.JPG (98.6 KB, 186 views)
File Type: jpg ToyStep09.JPG (94.8 KB, 186 views)
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  #2  
Old 08-26-2013, 05:58 PM
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And here's the other 2 Steps...
By The Way, 1 minute was allowed in between each step. Unsure as to actual length of time Toyota uses or Snap On is basing their testing on. This test is quite vague to me, so that's why I'm doing all this work to not only learn, but maybe teach someone else while I'm learning. I've asked about this before through this forum, but wasn't quite shown what I needed to see. Also, can someone tell me why so many OEM's only use 2 valves (Vent and Purge) and Toyota must use 3? This has had me perplexed since getting back into this industry 3 1/2 years ago. I shouldn't have to toss the book at every Toyota or see the other guys in the shop guess then I have to fix it for them. Guys, any tips or tricks would be appreciated. 30% or higher of our vehicle count through our shop daily is Toyota/Lexus, so it's kind of important to get this figured out.
Attached Images
File Type: jpg ToyStep10.JPG (93.7 KB, 192 views)
File Type: jpg ToyStep11.JPG (96.7 KB, 185 views)
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  #3  
Old 12-19-2014, 06:08 AM
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Default I would also like to stop pulling my hair out

Have you found any help with the evap testing yet.This test is quite vague to me also. And also to all of the shop owners around me. and anybody i have contacted from Snapon
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Old 12-19-2014, 07:03 AM
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Quote:
I proceeded to run the 11 Step test, and here's my results:
Gut Feeling says this will be back...
My gut feeling is macbob76 got Modis 500's comeback a year and a half later.
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Old 12-19-2014, 08:03 AM
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https://dl.dropboxusercontent.com/u/...0Key%20Off.ppt

Run this powerpoint in full screen mode. There is some animation in it.

It shows how the Monitor works and the data you will see on your scanner.

Joe
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Old 12-20-2014, 12:23 PM
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Joe,

There seems to be some significant differences between this 2011 Camry and the 2001 the poster is testing. Specifically, the presence of a vac pump.

I couldn't find the animation part (I'm admittedly not used to power point).

Last edited by Trindaddy; 12-20-2014 at 12:33 PM.. Reason: Needed to address who message is for.
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Old 12-20-2014, 12:32 PM
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Quote:
Originally Posted by Modis500 View Post
Also, can someone tell me why so many OEM's only use 2 valves (Vent and Purge) and Toyota must use 3? This has had me perplexed since getting back into this industry 3 1/2 years ago.
I agree Mr 500. What is the point to adding a vac pump to a system like this when it already has a vac source via the purge valve? For a company that works so closely with GM, I'm stunned that no one at Toyota sees just how simply GM accomplishes the task of recovering fuel vapors and how well it has worked for sooo long.

Anyway, what are the actual code(s) that present these days for your Camry? You didn't say.

Neil
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Old 12-20-2014, 02:46 PM
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Neil,

I can't remember the exact codes, as this was over a year ago. However, most of the mid-year toyota EVAP codes are 441,442,455. These are on 90% of the evap problem child cars. No tech I have worked with can explain the 3 valve system to me, and the ones that have tried always toss at least two components at every code that comes thru the door. I want specific answers, as I'm sure the customer feels the same way. I've done numerous EVAP system tests on known good systems, and I'm getting a barometer as to what is expected, however I will wait til I have conquered this functional test and can fully explain it on here to the other guys.

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Old 12-20-2014, 05:56 PM
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Quote:
Originally Posted by Trindaddy View Post
Joe,

There seems to be some significant differences between this 2011 Camry and the 2001 the poster is testing. Specifically, the presence of a vac pump.

I couldn't find the animation part (I'm admittedly not used to power point).
My bad! I didn't read it closely enough. I saw the post about the EVAP Functional Tests and I jumped right straight to the new Key Off systems.

Thanks for pointing it out.

Joe
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Old 12-20-2014, 06:31 PM
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Everyone may already know this, but Toyota and Nissan use 3 EVAP valves to leak check the fuel tank separately from the rest of the EVAP System.
It uses the purge and vent valves like anyone else, but has a bypass valve that isolates the fuel tank from the rest of the EVAP System. The car will run an EVAP Leak check with the bypass valve closed. This checks the entire EVAP system for a leak, except the fuel tank. Then it runs a second test with the bypass open so the leak check includes the fuel tank. P0440 codes can set if the bypass valve goes bad because the vehicle has the same vacuum decay when it runs both tests...and it knows that isn't right.

Older Toyotas can be a pain to leak check because there is a manual check valve on the canister that can't be closed off with the vent valve(like a normal EVAP System). This one way valve opens when the car is being refueled, allowing fuel vapors to rapidly escape the fuel tank. When testing under vacuum it is supposed to be sealed. So, any kind of pressure testing of the EVAP system will require the Tech to seal this vent off manually. The only way I know of to test for a leaky check valve is to do a vacuum leak check. If it leaks under vacuum but not pressure, I know it needs a new canister.
Also, mostly on Toytas of that vintage, it isn't uncommon for the isolation valve to fail open. Try cycling it on and off a bunch of times with the scanner. If it can do it 10 times without dying then it should be OK.

Check out slide #2 of the attached file. It shows what happens when you smoke check one of these old Toyota systems. There is no sense in closing the Vent Valve with the scanner. There is a check valve in the canister that prevents any pressure from escaping in that direction. So even if the Vent Valve fell completely off the vehicle no smoke would make it there from the canister. Also, you can see that there is a check valve that allows excess pressure in the system to vent without passing through the Vent Valve. This hose or port has to be pinched off to do an EVAP pressure test with a smoke machine.

https://dl.dropboxusercontent.com/u/...d%20Toyota.pdf

Lastly, the reason for the vacuum pump on the new EVAP systems of so the vehicle can run an EVAP check after the car is turned off. Most every manufacturer runs the Small Leak and Very Small Leak checks with the key off. Toyota wants to make their own vacuum with a pump instead of waiting for it to occur naturally when the tank cools off, like everyone else.

Joe
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