I/M readiness O2 not ready

Mooseman

Original poster
Moderator
Dec 4, 2011
25,257
Ottawa, ON
Next month I have to do an e-test, which is just plug in, verify for no codes and I/M readiness. I can pass if one test is not ready. The evap will never set in this cold weather and the O2 sensor portion is kicking me in the face and won't go to ready. I replaced the O2 sensors, replaced the air filter, cleaned the MAF, plugs were replaced in Sept. I tried the drive cycle posted everywhere on the net for GM and the generic one, no go. I'm not getting any codes and the trims are good.

In the past, the longest was always the evap to complete but with two, I can't pass the e-test. Any ideas?

This afternoon, I'll try to do the service bay evap tests with the Tech 2. I have to drive it 16 km and then bring into a heated garage for the non-running portion of the test. It failed when I tried it outside because it's too cold. I'm not sure if this will work because if it asks me to start the engine, my Tech 2 reboots (bug).
 

littleblazer

Member
Jul 6, 2014
9,265
You can trick the tech 2 by leaving it running, most tests I find will work like that.
I got my evap to run at 20 degrees last year. I went straight from a parking spot onto i95 and the light went out after about a minute. (I took a trip to Camden Yards, anyone who has been would understand how this is possible.) I know it's colder by you but it should work. (My tank was also half full)
 

Mooseman

Original poster
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Dec 4, 2011
25,257
Ottawa, ON
I was also able to trick it at the beginning of the test but I don't know if it will ask me to start the engine after the non-running portion in the service bay. If I can get the evap to complete, I'm golden.
 

littleblazer

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Jul 6, 2014
9,265
I don't recall if it does.
 

mrrsm

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This is a Long Shot... but the video shows a simple method of ridding any Dirt that has built up inside of the EVAP Charcoal Cannister ... and the technique might also help with cleaning any areas of the Charcoal that are densely packed with Fuel that will not get completely evacuated if the Purge Canister is not "Breathing" because it's air tubes are clogged. It probably would not hurt the canister by doing this and as long as it isn't knocked around too much to get the dirt loose. The one caution I would observe is that this should be done outside just in case there is any Static Electric Discharge introduced by the compressed air... Wouldn't want to see @Mooseman wind up in a Polar Orbit. :>)

 

Mooseman

Original poster
Moderator
Dec 4, 2011
25,257
Ottawa, ON
Well crap! Started the evap test and during the drive, went below 1/4 tank so it failed. Put some gas in it a d waiting for the coolant temp to drop below 70c. In -13c, it's dropping fairly quickly. This is still a PITA!
 
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Nexus1155

Member
Jan 26, 2012
141
Couple things. Check the O2 wiring on driver side to check for proper function. If not possibly a failing cat. Do you have a tuning suite? Couple things you can do. Disable evap mil in total. Or. Gut the cat and disable the o2 mil. Or. Replace catalyst? If you replaced o2 sensors with proper ones and wiring signal is fine this is where you're at i believe. Possibly if they are driven by the ecu itself the internals of ecu may be burnt up?
 

Mooseman

Original poster
Moderator
Dec 4, 2011
25,257
Ottawa, ON
Cats are good as that test passed. If there was an issue with the wiring, you would think that I'd get a code, no? ECU's either work or they don't so I don't believe that is the issue either. I think it's related to the cold weather. I know the evap is very fussy to pass.

PS: Tried to do a second service bay evap test and I couldn't trick the Tech 2 so the engine warmed up above 70c again. I think the trick only works on a coldish engine.
 

Nexus1155

Member
Jan 26, 2012
141
The evap youre definitely going to have issues with i think regardless. It is cold and finicky. The o2 i have seen much stranger things happen to my audi. Regardless if cat passes readiness or not. Even if the wiring is good i was saying it could be the driver circuit. I have had to replace ecus before to pass readiness, but all in all youre right it could just be related to the cold. Strange if it didn't go away yet though after a cycle.
 

littleblazer

Member
Jul 6, 2014
9,265
With the plug in emission test you go to jail if you tune out the light...

So the O2 sensor isn't ready. What exactly is that if I may ask. It could maybe be the heater circuit?
 

Mooseman

Original poster
Moderator
Dec 4, 2011
25,257
Ottawa, ON
No, it has it's own test, which it passed. Not sure what it is exactly it's looking for. Both are new and they're working like they should. No codes anywhere.

Tried to do the service bay test again, got past the drive portion this time but the mall garage I went into wasn't warm enough so it failed. I may try again after my night shift and bring in to my work's heated garage. This time I'll let it sit for an hour before the test to be sure it picks up true ambient temperature.
 

littleblazer

Member
Jul 6, 2014
9,265
Put a resistor in place of the temp sensor to trick it?
 

Mooseman

Original poster
Moderator
Dec 4, 2011
25,257
Ottawa, ON
That's an idea. I'd have to find what resistance equals which temperature. I'll see how it goes tonight and if that fails, the outside temp is supposed to go up to +7c on Thur and will retry then.
 

Mooseman

Original poster
Moderator
Dec 4, 2011
25,257
Ottawa, ON
Woot! I was able to complete the evap Service Bay Test last night. The temperature was +2c outside. Did the drive, took into a heated garage, waited about 15 minutes and then did the engine off portion of the test and was completed in about 5 minutes. Funny thing is that the ambient temperature still showed as +2c. Didn't take a chance and did my e-test this morning. The O2 sensor was still not ready but that's OK as they will accept one not ready.

If I didn't have my Tech 2, I would have never been able to get this done. I still wonder why the O2 won't complete. Searching the net, I still don't know what it's looking for.

I'll probably post a How-to in the Tech 2 section on how to do the Service Bay Test.
 

littleblazer

Member
Jul 6, 2014
9,265
Hey @Mooseman, This was on the 5.3l correct?
 

Mooseman

Original poster
Moderator
Dec 4, 2011
25,257
Ottawa, ON
That's right.
 
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littleblazer

Member
Jul 6, 2014
9,265
Ah. So I can't force run the i6 then. Alright, thank you. :tiphat:
 

Mooseman

Original poster
Moderator
Dec 4, 2011
25,257
Ottawa, ON
The evap systems should be close to being the same so you should be able to do it too.
 

littleblazer

Member
Jul 6, 2014
9,265
The evap systems should be close to being the same so you should be able to do it too.
I did the drive cycle method. Took it out the end of my block and did 45 for a couple miles. Light went out at mile 3. :dance: when I try to launch the service Bay test for a 5.3 it fails and says improper vehicle. The i6 doesn't list that test as available. :confused:
 

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