CEL came on yesterday, 2006 ODB trouble codes

[2006Tahoe2WD]

I'm feeling the old switch. It has 3 detents and a spring loaded feel on one end (starting mode).
1 - accessory
2 - off
3 - run
4 - spring rotate to start
With the key out (off) I need to put the switch on the "off" detent and then slide in the switch.
Does that make sense? That method is not described in the videos.

 

[OR VietVet]

I'm feeling the old switch. It has 3 detents and a spring loaded feel on one end (starting mode).
1 - accessory
2 - off
3 - run
4 - spring rotate to start
With the key out (off) I need to put the switch on the "off" detent and then slide in the switch.
Does that make sense? That method is not described in the videos.

Frankly, I did not care about what circuit was effected by the gear teeth location. If I had a vehicle that was cranking and starting and then was not and I was replacing the ignition switch, I am going to replace with the gear teeth in the same position. I showed on the 2 videos where the teeth are located and what I did. It now works after correcting the teeth alignment. I can now sleep at night.

 

[2006Tahoe2WD]

I'm reminded of something my Dad used to say. If all else fails try reading and following the directions. Well.... I thought what about looking in the manual. Guess what ? I thought the far counterclockwise direction was ACC. It is not - it is the "LOCK/OFF" position (key can come out). The next position in the clockwise direction is ACC, then RUN, then START.
The 2006 doesn't have the steering wheel lock feature. Not sure about other nearby years.

 

[2006Tahoe2WD]

Update - I moved the gear over about 1 tooth. All works good now.

I'm now starting to dig into the P0442 code.
I hooked up my code/scanner tool and got the purge valve to come on and watched the fuel tank pressure go down. When I shut the purge valve off the fuel tank pressure came back up to ~0 very quickly. I took the purge valve out and pulled a bit of a vacuum with my mouth and it held. I also noticed when I manually opened the purge valve with the scanner there was a stumble in the idle. The gas cap O ring and seal looked okay - no cracks in the O ring.
I don't have a smoke tester - what can I do next?
Thanks.

 

[Fless]

So I understand it, it sounds like you did a purge and seal test, but the vacuum that was applied during the purge didn't hold after the seal, and the fuel tank pressure returned to atmospheric pressure very quickly. Do I have that right?

When you removed the purge valve, what did you pull a bit of a vacuum with your mouth on? The purge valve, or the intake?

And yes, at idle, when the purge valve is opened the idle will get rough and the engine won't be very happy. Normal.

Purge valves (as well as vent valves) can be intermittent, so be careful with that.

EDIT: you can test the vent valve to be sure it's closing mechanically and electrically.

 

[2006Tahoe2WD]

So I understand it, it sounds like you did a purge and seal test, but the vacuum that was applied during the purge didn't hold after the seal, and the fuel tank pressure returned to atmospheric pressure very quickly. Do I have that right?

When you removed the purge valve, what did you pull a bit of a vacuum with your mouth on? The purge valve, or the intake?

And yes, at idle, when the purge valve is opened the idle will get rough and the engine won't be very happy. Normal.

Purge valves (as well as vent valves) can be intermittent, so be careful with that.

Not 100% sure I did the purge and seal test correctly. I did see the purge valve open in a percentage manner on the reader and the fuel tank pressure went down. I pulled the vacuum in both directions on the purge valve and didn't feel an obvious leak.
It seems like when the purge valve closes the negative pressure should stay or decline slowly.

 

[Fless]

Near the end of this video Eric O shows the purge and seal test, and how to understand the fuel tank pressure and vacuum decay.

MORE: Mike at Wells does a great job of explaining and testing:

 

[OR VietVet]

Update - I moved the gear over about 1 tooth. All works good now.

I'm now starting to dig into the P0442 code.
I hooked up my code/scanner tool and got the purge valve to come on and watched the fuel tank pressure go down. When I shut the purge valve off the fuel tank pressure came back up to ~0 very quickly. I took the purge valve out and pulled a bit of a vacuum with my mouth and it held. I also noticed when I manually opened the purge valve with the scanner there was a stumble in the idle. The gas cap O ring and seal looked okay - no cracks in the O ring.
I don't have a smoke tester - what can I do next?
Thanks.

You moved the tooth over 1 tooth? You rolled the fat/wide spot where it is hidden/cannot be seen and now all is good? Correct?

 

[2006Tahoe2WD]

You moved the tooth over 1 tooth? You rolled the fat/wide spot where it is hidden/cannot be seen and now all is good? Correct?

Yes, the flat spot was already rolled over a bit and I rolled it an additional tooth and all seems good. Thanks for all the info.

 

[OR VietVet]

Yes, the flat spot was already rolled over a bit and I rolled it an additional tooth and all seems good. Thanks for all the info.

So, basically, as long as you make that fat/wide spot disappear, it is aligned correctly, but don't over do it and go too far.