How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Tims Auto Repair Your Own Question
Tims Auto Repair
Tims Auto Repair, GMC Mechanic
Category: GMC
Satisfied Customers: 15636
Experience:  have owned a repair shop for 25 years
14541291
Type Your GMC Question Here...
Tims Auto Repair is online now
A new question is answered every 9 seconds

2007 GMC Yukon Denali I have code p0442. What would cause

This answer was rated:

2007 GMC Yukon Denali
I have code p0442. What would cause this?

Hello and welcome. My name is ***** ***** you for visiting the site, I am reviewing your question and will reply shortly, thanks.

DTC P0442
Evaporative Emission (EVAP) System Small Leak Detected

  • The control module detects a leak in the EVAP system that is greater than a calibrated amount.
Customer: replied 4 months ago.
I have the code description. What is the likely place this happens

I see, thanks. A lot of times it is just a bad gas cap but if not, or if you tried that already the test would have to be done to be sure.

Customer: replied 4 months ago.
What test

The diagnostic test for the specific code(s) that was offered to you.

Customer: replied 4 months ago.
I dont understand what test you are referring to. Test with a diagnostic scanner? a smoke machine? what?

Actually both. There also was a factory service bulletin for a P0442 to aid in diagnosing it.

Customer: replied 4 months ago.
ok, can I get that bulletin?

Sure thing.

Here is a link to what it states. You can copy and paste it into a new browser and rate the answer on this page.

.

https://www.dropbox.com/s/o4p07oz3o48jiqv/EVAP%20DTC%20P0442%20DIAGNOSIS.pdf?dl=0

.

Please don’t forget to rate the answer in a positive way, . EVEN IF YOU HAVE A SUBSCRIPTION ****THAT IS THE ONLY WAY I GET PAID ****

Did you get that?

Customer: replied 4 months ago.
No it says the file is. It there anymore
Customer: replied 4 months ago.
File isn't there anymore

Hi, My name is ***** ***** for the delay.

I will do my best to assist you.

here is the tsb and the code definition/tests

thanks

PLEASE COPY AND PASTE the link below to your browser, I have uploaded more info on this there please copy and paste the link below to your main browser[INTERNET EXPLORER or FIREFOX]

.

https://www.dropbox.com/s/35uoe4fg7m0xgsz/0926%3Dgmc-PIT4943C.doc?dl=0

.

if the link doesn’t work that way, try it this way

thanks

.

www.dropbox.com/s/35uoe4fg7m0xgsz/0926%3Dgmc-PIT4943C.doc?dl=0

.

If you are satisfied with my answer, Please Rate my answer by clicking the rating button so I can get credit for my work. I’m not always going to be giving you good news, so please don't let this stand in the way of you accepting my answer. .it does not cost you more money and we will still be able to communicate, ,.please understand, i can not see, hear or touch the vehicle and only know what you tell me. Bonuses and positive feedback are appreciated.. if you are not satisfied with my answer, please do not leave bad feed back ,i will gladly opt out and let another expert handle the question. .if i have sent any diagrams, please print them. .sometimes you may need to right click the image [,then save picture as]to save it to your computer so you can open it with your picture program...Please ask if you need more help

Customer: replied 4 months ago.
really I need a smoke machine to test this or will a scanner suffice

a smoker would be best..a scanner by itself may not help much

Customer: replied 4 months ago.
Ok. Well when I was filling up with gas just now I could hear it sound like it was getting full then it would abate and keep filling them it would sound like it was filling up again. This happened a few times.

that wouldnt have anything to do with a vapor leak..

you need to make sure your gas cap is good,,if so,,smoke the system

thanks

Tims Auto Repair, GMC Mechanic
Category: GMC
Satisfied Customers: 15636
Experience: have owned a repair shop for 25 years
Tims Auto Repair and 3 other GMC Specialists are ready to help you