PCM P0451 2015 GMC Sierra All-Terrain

[lschafroth]

I have kicked this code 4 times now in 2 weeks. I clear it with my tuner. I have noticed it only shows up when I try to remote start it with the Fob or using the app on my phone. Normal starting never appears to set the code.

I looked under the truck and all the lines look perfect. Not sure if you can really diagnose the canister etc visually.

Any thoughts as to why the remote start seems to trigger the code? Does it do more testing before a remote start?

Should I start with the purge valve or the sensor? Both are very easy to get to.

Lannie

PS 122,000 miles on it already. 5.3L Flex. 6Speed

 

[Sparky]

Evap... emissions related. Is that still under warranty? Maybe not due to miles... if it is, I'd be tempted to make them figure it out, as evap is the most obnoxious system to figureout and fix, IMO.

 

[djthumper]

In the 2015s there have been reports of faulty pressure sensors tripping that code.

 

[lschafroth]

In the 2015s there have been reports of faulty pressure sensors tripping that code.

I'll replace the sensor to start with and see what that does.

Lannie

 

[lschafroth]

OK, I thought I knew where the sensor is but I cannot find a diagram anywhere.

Lannie

 

[djthumper]

On top of the tank

 

[lschafroth]

My son crawled under, reached over the top of the tank while looking at a pic of the fuel pump assembly on his phone. Pulled it out and replaced it without even a floor jack or tools. The rubber part broke off in the assembly and he was able to pop that out blindly as well.

Easy fix, and the remote start works.

 

[lschafroth]

I forgot to say THANKS!!! Thank you to everyone who offered suggestions and took the time to post a video for me.

Lannie