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Super Mechanic
Super Mechanic, Master technician
Category: Chevy
Satisfied Customers: 17203
Experience:  29 yrs. exp., ASE master, cert. in G.M. electrical, a/c, susspension, brakes, electronic steering
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2007 Chevy Tahoe LTZ, 4WD, with 5.3L Flex Fuel with 97,000

Customer Question

2007 Chevy Tahoe LTZ, 4WD, with 5.3L Flex Fuel with 97,000 miles
I have recently been chasing a DTC P0442, EVAP Emission System Leak Detected (Small Leak). Code was first set approximately 1.5 months ago. I have already followed the guidance provided in TSB#: 09-06-04-028D. To date I have replaced the following items, and in the following order using ACDelco replacement parts in all cases:
Gas Cap P/N 20915990
Vapor Canister Vent Valve P/N 23481275
Jumper Wiring Harness P/N 19257603
Vapor Canister Purge Valve P/N 12597567
The only items which I have not replaced are the vapor canister and fuel take pressure sensor.
After replacing the parts already listed I once again set DTC P0442. So using a OBDII Scan Tool, I examined the diagnostic information for EVAP (0.020"):
Test: $C8
MOD: $00
MAX: 0.648
MEAS: 0.672
MIN: 0.000
STS: HI
Test $C9
MOD: $00
MAX: 0.727
MEAS: 0.031
MIN: 0.000
STS: OK
Additionally, I do not have the characteristic hard to fill gas tank. I did inspect the old Vapor Canister Vent Valve and it was full of dust and fine particle dirt, so much so that I could dump the dirt out of it.
My question is, do I now replace the vapor canister or look elsewhere?
Submitted: 11 months ago.
Category: Chevy
Expert:  Super Mechanic replied 11 months ago.

Hello and welcome. My name is ***** ***** you for visiting the site.

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Let me just say that any money that you paid, or if you have a subscription, that money stays in your account until the answers are rated, (positive) regardless of how fast or how long it may take to get finished. You can FOLLOW UP AT ANYTIME, even after rating.

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That could very well be the canister. They sometimes get a small crack around the seam on the top and create a small leak. With all of the other parts that have been replaced and the bulletin being addressed, that is almost the only thing left. However, the best way to find an EVAP leak is with a smoke test.

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If you accept my additional service request for your email address, you can give me your email in a private info box and I'll send you the test instructions in a PDF file, the file is rather large.

You will just have to accept the additional service offer and ENTER your email address in the “ENTER CONTACT INFO” section so that I can see it, Thanks

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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 ****

Expert:  Super Mechanic replied 11 months ago.

It shows that you are waiting for me. let me send this as a test, thanks

Expert:  Super Mechanic replied 11 months ago.

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 ****