13.4 Evap test on 06 GMC truck???

[SnapOnKid]

Any one run the Evap test with 13.4 software on a Chevy or GMC truck lately?

Specifically I did this on an 06 GMC 1500 Flex Fuel truck that I recently purchased.

It has you run the RPM between 1800-2200 for a set period of time while it test the system. The test ran fine and told me to do the drive test for 10 miles and so many seconds. The drive test went fine and it told me turn the Engine off but ignition on while it ran another test that would take up to 10 minutes.

I pulled over and followed the directions but it would never complete the test. It ran for 20 minutes. If you turn the ignition off it will lose connection. If you turn the engine on it errors out and says it can not complete the test.

I was under the gun so I couldn't spend all day trying to document everything.

I was wondering if any one else had trouble with this test working properly???

I was going to try and mess with it again over the weekend.

I didn't want to break the Tech2 out since I was already using the Verus.

[Crusty]

AFAIC the GM Evap Service Bay Test isn't worth messing with. In order for it to "enable" you have to clear codes which kinda defeats some of the benefit of running a dedicated EVAP monitor.
About the only thing it does is relaxes the temperature parameters for the system to self test.
Check the conditions required for the system to self test for a P0440 or a P0442 and then operate the vehicle under those conditions.
Basically IAT and ECT within about 10-F of each other, IAT and ECT between 40-F and 75-F (different vehicles vary),Fuel level Above 25% and below 75% (different vehicles vary), run the vehicle for about 15 minutes (or more), then come to a stop and in park for 30 seconds or more, then shut down normally.
Here's the kicker so you know the vehicle IS actually doing the self test.....with the key off and out in your hand, the ECM will stay awake and continue to send data to your SnapOn scanner. Monitor the EVAP data group during the entire sequence from start to finish. Take screen shots and movies about 1 minute apart so you have a record of the activity and you can watch the system seal, build pressure, then cool and drop the pressure from a positive pressure down to a negative pressure (vacuum).

The neat thing about the SO scanners is they are recording the data in their internal buffer as long as the ECM is delivering data (awake).
The bummer about SO scanners is they LOSE that data when the ECM stops delivering data (goes to sleep) and you get the "no communication" screen.

In other words, they dump the data in the buffer as soon as the com is lost, thus the need to save multiple screen shots and movies about 1 minute apart because we never know exactly when the ECM will be satisfied that the self test is complete.
The ECM may have decided it isn't happy with the results and quit fairly quickly, or the conditions for the self test listed in the P0442 code chart were not met and quit almost immediately.
IF you have the key out and in your hand, open and close the driver door to shut down the Retained Accessory Power (RAP). If the scanner still has communication, the self test is running. I have seen this automatic self test take as long as 40 minutes to complete and be "happy" with the results and complete the monitor with a "pass" and no codes stored or pending.

The values I have indicated above are generic but should put you in the window for most of the GM vehicles that use the EONV evap test.

(I wish the scanners wouldn't "dump" the buffer so we could just turn the key to the "on" position to restore com and then save a movie of the data so we could save and see what the conditions were when the ECM was either unhappy, or happy, with it's self test sequence)
(they DID fix this on the Solus-Pro a few years ago but I havn't checked it recently as the Solus-Pro has caused voltage spikes in a 2009 GM mini van and I'm not sure whether they fixed THAT or not and I don't feel like paying to replace the instrument cluster AGAIN now that the vehicle is out of warranty)

Never mind the SBT. Just operate the vehicle as described for the vehicle to self test listed in the EVAP code set parameters. MOST of the time, either way, is sitting waiting for the Fuel Tank Pressure to rise and then fall a certain amount.
If you WATCH the FTP pid as it self tests, if you see about Plus 2 inH2O and then Minus 4 inH2O, the vehicle is usually happy with that.
HTH

[Joe Rappa]

I've never had the key-off portion of that test run in under 20 minutes. It can take up to an hour.
You may already know this, but when the scanner tells you to stop the car and turn the key off, you don't have to do it right then. Those are minimum numbers. When the timer and mileage expires drive the vehicle back to your shop and park it where you don't have to move it for an hour. Wait for the test to finish. I like using that test when I'm doing an emissions inspection. GMs will generally run all the monitors while this test is running as long as you do a sensible road test.

Joe

[Crusty]

I've never had the key-off portion of that test run in under 20 minutes. It can take up to an hour.
You may already know this, but when the scanner tells you to stop the car and turn the key off, you don't have to do it right then. Those are minimum numbers. When the timer and mileage expires drive the vehicle back to your shop and park it where you don't have to move it for an hour. Wait for the test to finish. I like using that test when I'm doing an emissions inspection. GMs will generally run all the monitors while this test is running as long as you do a sensible road test.

Joe

That's a good point Joe. You don't have to shut it down right then and there. You can take the vehicle back to the shop and then shut down.

With a lot of fuel in the tank but low enough for it to run, I've seen the systems manipulate the small vapour cavity faster. Sometimes in as little as eight minutes. Perhaps the cool ambients up here in Canuck land allows the vapour to cool faster.

[SnapOnKid]

Thanks for the heads up guys! I will give it another shot today.

Everything else seemed to go fine. At the time it was about 3/4 of a tank full. Now it's closer to 1/2


IIRC The test said it would take 10 minutes to complete the last part. Thats what had me confused. I will pay closer attention today.

[Joe Rappa]

I've seen the systems manipulate the small vapour cavity faster. Sometimes in as little as eight minutes. Perhaps the cool ambients up here in Canuck land allows the vapour to cool faster.

That is fast! I've never seen one go so quickly, but I'm sure you do a lot more of them than I do. I didn't think the Monitor was capable of making a decision so quickly. Good to know.

Joe

[SnapOnKid]

That is fast! I've never seen one go so quickly, but I'm sure you do a lot more of them than I do. I didn't think the Monitor was capable of making a decision so quickly. Good to know.

Joe

Joe, Do you have access to a tech2 or MDI? It will complete that fast. I believe Crusty is onto something with the cold bring the engine temp down.

After literally wasting all Day, It seems I may have found my Problem. While the software is the same across all platforms, The wireless units are different in terms of the module.

I believe in order to perform this test correctly I need to use the USB cable to attach the S3 module to the Verus. With the last portion of the test you need to turn the ignition off as prompted but not remove the key. Without the USB cable connected It would loose connection. The Tech2 will just sit there until you turn the key all the way off. After you turn the Key off then it will Perform the test. The Tech2 shows you that the test is running on the screen along with certain values.

I will have to put some Tech2 photos I took with my phone up later.

Now that I know that I Guess this thread should get moved to the Evap section.

[SnapOnKid]

Well, looks like I spoke too soon. This time when I got to the end of the test, The scanner locked up when I turned the Key off.

Talk about pissed!!!

I had to use the power button to get it to shut off. Then it wouldn't power back on so I had to pull the battery. Now the accessory rubber sleeve is torn.

I hope I don't have to send it in for some sort of repair.

[Crusty]

That is fast! I've never seen one go so quickly, but I'm sure you do a lot more of them than I do. I didn't think the Monitor was capable of making a decision so quickly. Good to know.

Joe

LOL....I don't do as many as you do-!! I just had to learn the systems really well when SnapOn wouldn't display ALL the pids....ROFLMAO. In fact I should thank SO for doing that because I found that all North-American, Asian and European manufacturers are looking for the same things.

On GM's I found that normal driving will produce about 1.0 to 2.0 inches of WATER COLUMN (negative from atmospheric pressure).
IF the Cold-Start conditions to enable the vehicle to self test are met, they will self test the same as the non-CAN vehicles during the initial start and run cycle (regardless if you have initiated the SBT or not)
On shut down, the ECM/PCM will look at the vacuum/pressure, release it by turning the Vent solenoid off so it's open to atmosphere, then look to see the change in the Fuel-Tank-Pressure does go to Zero, then it will close the Vent (the purge stays closed because the engine isn't running).
The system will then expect the heat from the fuel being returned agitating the liquid (on the return systems) and the heat from what was a running electric motor (fuel pump) and the heat from ambient under-vehicle things such as exhaust systems and converters, to then increase the Zero-atmospheric pressure up about 1 or 2 inches of WATER Column.
THIS is where the time it takes the vehicle to complete it's self test becomes variable. If there is 15 to 20 percent fuel remaining in the tank, there is a larger vapour cavity which will take longer to pressurize. If there is 70 to 80 percent fuel remaining in the tank, the vapour cavity above the fuel is smaller and will change pressure faster.

Put a large balloon and a small balloon in the sun on a window sill. Then remove them both from the window sill. The large one will take longer to expand and will take longer to cool and contract than the smaller balloon.

The vehicle now knows it can create a pressure (albeit small it is still a positive pressure). If the cavity of vapour is small, the cold fuel and the cooling of the undercar components allows this vapour cavity to cool down to a vacuum faster as well. Usually only about 1.5 to 3.0 inches of water column. Again not very much but the ECM/PCM is satisfied that if it can create a pressure, then in a reasonable period of time it sees the system sealed enough to create a vacuum, it concludes that there isn't a sewing needle hole, or larger leak, in the system.

There have been a few vehicles where merely having the scanner plugged in has inhibited the ECM/PCM from completing the EVAP/EONV self test somehow. (EG: 2002 Impala)

It's been GREAT to simply look at the EVAP data group, watch the pids that are thankfully now in there, see the IAT, CTS and FTLevel, then watch the FTPressure, all from a cold-start, through the start-run-warm up, then watch the data pids and watch the FTPressure after shut down. THE ECM STILL IS AWAKE while it self tests. The scanner still displays data while the ECM is still awake.
The problem that still remains with the Solus-Ultra, and I believe the majority of the scanners is that the second the ECM is happy with what it has seen, it shuts down and the scanner says No-Communication.

The PROBLEM is that the scanner also clears and dumps the recording buffer so unless you're watching the pids like a hawk, we don't know at what point the ECM was satisfied and finished with the test.

They DID FIX this characteristic on the Solus-PRO a few years ago. All we had to do was turn the ignition back to the ON position to re-establish communication and then immediately save a movie. This then held the last few seconds of data just before the ECM was satisfied and shut down and went to sleep.
I hope they havn't messed up the Solus-PRO on this point of not dumping the buffer. They should make all the scan tools retain the data in the buffer until we exit the data group, not immediately on ECM sleep mode.

Use the MANUAL Purge/Seal function (much faster) instead of the SBT (much slower). At idle, it will max out and abort with as little as 30% purge and you can see the maximum Inches-Water-Column vacuum reach the limit of that particular vehicle (usually between 8-inH2O and 13.5-inH2O)
Then just drive the vehicle within the "enabling conditions" for P0442 (small leak) and check the monitors on the next key-on cycle.

HTH somebody sometime.

[Modis500]

I gotta say sometimes I leave here with a good laugh. Snap On Kid, where can I order one of those golden stirring spoons? I cracked up when I seem that on your heading.

[Crusty]

I gotta say sometimes I leave here with a good laugh. Snap On Kid, where can I order one of those golden stirring spoons? I cracked up when I seem that on your heading.

I guess SnapOnKid is "Royalty" from Europe with his spoon....
Skip has his Magic-Eight-Ball and Ericsautomotive has the Diagnostic-Dice...LOL

EVERY shop and Tech should have a set of those Dice-!!! Just hand 'em to the customer and let them decide what they want you to do....ROFLMAO

[SnapOnKid]

I gotta say sometimes I leave here with a good laugh. Snap On Kid, where can I order one of those golden stirring spoons? I cracked up when I seem that on your heading.

I guess SnapOnKid is "Royalty" from Europe with his spoon....
Skip has his Magic-Eight-Ball and Ericsautomotive has the Diagnostic-Dice...LOL

EVERY shop and Tech should have a set of those Dice-!!! Just hand 'em to the customer and let them decide what they want you to do....ROFLMAO

Nope, Just a Gold Ole Self taught Grease Monkey.

I have it on good faith That I have metaphorically stirred pot a time or 2...

So I thought I would list it in my Diagnostic tools used...

What Can say, it has actually worked even if it's just a metaphorical tool.

[SnapOnKid]

So update on what I found the hard way.

I re-scanned the truck and it completed the test even though the scan tool locked up. Apparently the test completed even though the scanner locked up and could not display that information.

The truck was not started or moved after the scanner locked up.

I have not been able to get in touch with my local dealer to inquire about sending the scanner in. I believe 1 of the cooling fans may be failing.

Even though the scan tool is out of warranty, it is my personal scan tool that stays in a climate controlled area in it's original case. It has only been used a handfull of times and only by me personally. Used on less then 50 cars. I am very meticulous with my stuff and never let it out of my site, even for the Software updates. I usually have to step in during the update process and take over as my dealer only has maybe a handful of these on the street and people like to skip software updates in this area. I have seen guys go average 2-3 years and in a few cases 4 years between updates.

I must say that's a little disappointing and I am concerned that if the small fan is failing what's next? A hard drive?

After Pushing to see extended warranties on such an expensive item, they finally did it. Unfortunately when they did it was too late for me when they offered it as mine was out side of the range on how far they would go back.

Also looks like the rubber skin may have been discontinued too...

If I don't hear from him, I may just call tech support and see if I can get an Idea of cost.