Help clearing code

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2010gmcyukon

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I got the P0442 code this weekend (evap system leak). I first checked the gas cap, and behold it was actually very loose. Not sure how I did that, but ok. Tightened the cap and drove around a bit, still hasn't cleared. I filled the gas and re-capped, the check engine light is still on.

The scanner I used to read the code does have an erase code function. I turn the ignition to ON (but engine off) and plug it in. When I select erase code, I get the message "erase failed". Not sure if this is because I'm doing something wrong or what. Anyone have any ideas?

I realize that if there is still an issue the code will come back...but it should at least clear right?

This is the scanner.
https://www.amazon.com/gp/product/B07PFMB8YS/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
 

wsteele

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It should clear it. But since it’s not, that code will clear on its own pretty quick. Not sure how many drive cycles it takes but it will clear on its own if the issue is resolved.

This.

It probably is what is known as a Permanent code, that is, you can't clear it, the system has to clear it after the internal evap monitor is satisfied it is fixed and that takes driving cycles. On my truck evap seems to be the hardest monitor to satisfy (takes the most driving and cycles, I have read stuff about running it down to half tank, etc. to get it OK status).
 

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I got the P0442 code this weekend (evap system leak). I first checked the gas cap, and behold it was actually very loose. Not sure how I did that, but ok. Tightened the cap and drove around a bit, still hasn't cleared. I filled the gas and re-capped, the check engine light is still on.

The scanner I used to read the code does have an erase code function. I turn the ignition to ON (but engine off) and plug it in. When I select erase code, I get the message "erase failed". Not sure if this is because I'm doing something wrong or what. Anyone have any ideas?

I realize that if there is still an issue the code will come back...but it should at least clear right?

This is the scanner.
https://www.amazon.com/gp/product/B07PFMB8YS/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1


It says it has lifetime software updates, so make sure it's been updated to the latest version.
 
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2010gmcyukon

2010gmcyukon

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This.

It probably is what is known as a Permanent code, that is, you can't clear it, the system has to clear it after the internal evap monitor is satisfied it is fixed and that takes driving cycles. On my truck evap seems to be the hardest monitor to satisfy (takes the most driving and cycles, I have read stuff about running it down to half tank, etc. to get it OK status).

Thanks guys, this makes sense. It did say "permanent code" when I was viewing it, but I'm a noob with scanners so I didn't know what that meant. I'm still 100% work from home right now so its not getting much drive time. I'll try to take some extra trips to see if it clears. Hoping it was just the gas cap and not the other parts causing the code.
 
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2010gmcyukon

2010gmcyukon

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It says it has lifetime software updates, so make sure it's been updated to the latest version.
Thanks, I will update it. Based on some other comments here, it sounds like I may have to wait for the code to clear itself.
 

wsteele

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Thanks guys, this makes sense. It did say "permanent code" when I was viewing it, but I'm a noob with scanners so I didn't know what that meant. I'm still 100% work from home right now so its not getting much drive time. I'll try to take some extra trips to see if it clears. Hoping it was just the gas cap and not the other parts causing the code.

There are a few GM trip cycles online that supposedly checks all the boxes and should clear permanent codes. Frankly, it never worked for me, but I will admit to not following it exactly, so maybe that is why it didn’t work.

Here is one:

http://www.obdii.com/drivecycle.html
 

Rocket Man

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There are a few GM trip cycles online that supposedly checks all the boxes and should clear permanent codes. Frankly, it never worked for me, but I will admit to not following it exactly, so maybe that is why it didn’t work.

Here is one:

http://www.obdii.com/drivecycle.html
Yeah, I couldn’t follow that drive cycle because it’s impossible unless you live on the GM proving grounds so you can wake up and have a place to accelerate at half throttle to 55, hold for 3 minutes, then decelerate to 20 without touching the brakes...try that on a freeway around here and you’ll be dead.
 

wsteele

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Yeah, I couldn’t follow that drive cycle because it’s impossible unless you live on the GM proving grounds so you can wake up and have a place to accelerate at half throttle to 55, hold for 3 minutes, then decelerate to 20 without touching the brakes...try that on a freeway around here and you’ll be dead.

Same here. I did the deceleration from 55 thing on a deserted part of an 8 lane freeway (both ways) and as I was decelerating, a guy comes bombing upon behind me in the far right lane (3 clear lanes to the left) and starts honking and shaking his fist. No exits ahead for 2 miles, I guess I really hindered his forward progress... :).
 

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