I have a check engine light coming on in my 2007 Silverado. Consensus is that is a plugged Evap Cannister and or purge valve. My question is are these dealer only parts or will they be available at an OReileys etc. and if so how much?

Call O'Reileys and AutoZone and see. It might be a dealer only item and it may not. If its not and one of these stores carries the part, it might be cheaper. And even if its isnt a part you can buy at a retailer, check other reputable mechanics because they will probably be cheaper than the dealer when it comes to part cost and labor cost.

what code is it giving you.the 07 trucks had a problem with the purge valve,and sometimes the vent valves due to there location would get small particles of sand in them and stick,we started putting old pantyhose over the vent valve's to keep the dirt out.Also how many miles on your truck.

Need the code to diagnose. There is a TSB for the evap solenoid.

O7 dont normally need a canister, in my 20yrs as a master tech haven't replaced maybe 2, probably has a leak in the evap system it will need to b smoke tested, a code would b nice, its funny people want answers to prob. but wont repost vital info

Im sorry dont have a specific code. But had it read at autozone and they said it was gas cap or Evap system leak. Have noticed that pump cuts off a lot when I fill up like a vapor lock. Another forum mentioned cannister was likely cause. Was hoping for an easy fix. Also Truck is 5.3 Z71 Flex fuel with 70,000 miles. I will have code read again and get specifics.

Well it would be good to know the specific code the PCM is generating. I've experienced simular issues with my 97 F150 and my daughter's Mustang. There are alot of things it could be as in the case of the daughter's mustang it turned out to be the donut seal where the filler neck goes into the fuel tank and didn't become apparent until the second time she was rear ended. Shortly after the body shop fixed the damage we found the seal had a severe crack and the neck was misaligned with the inlet of the tank the PCM was coding a severe leak but we kinda figured it out on our own because we has a major fuel odor especially when she re-fueled. Secondly on my F150 has thrown a P0442 (small leak) about every six months to a year for the last 7 or 8 years. I've posted this on the F150 forums and gotton these responses and made all of the checks suggested and did not find any definate problems other than my problem may be the purge valve. So far it has been so intermittent that I haven't worried about it but will more than likely replace it when the weather permits. I normally just reset the PCM and see how long it takes to come back (like I said as soon as in 6 months to a year) doesn't matter if I do a hard boot on the PCM (removing the neg cable on the batt) or soft reset with my tuner, or a code reset with my code reader. If your having issues with a vapor lock problem when re-fueling then look at the neck and all of the connections. I heard from a guy that had the weld break loose on the internal baffel in his filler neck. Once you check all of the hoses for cracks or pin holes and the return line for obstuction then there is little left but the canister (again check it for damage) then that leaves the purge valve. Just cosider the source coming from a Ford guy but the emission systems on all vehicles will be some what simular in design. Here is the responses I got through e-mails on things to check you also might try to find a diagram of how your system is layed out as well hope this helps.

P0442 EVAP Control System Leak Detected (Small Leak) Detailed Description.............. The PCM monitors the complete EVAP control system for presence of a small fuel vapor leak. The system failure occurs when a fuel vapor leak from an opening as small as 0.10 cm
(0.04 inch) is detected by the EVAP running loss monitor test.
Possible causes :- After-market EVAP hardware (such as fuel filler
cap) non-conforming to required specifications. Small holes or cuts in fuel vapor hoses/tubes. Canister vent solenoid stays partially open on closed command. Damaged, cross-threaded or loosely installed fuel filler cap. Loose fuel vapor hose/tube connections to EVAP system components. EVAP system component seals leaking (EVAP canister purge valve, fuel tank pressure sensor, canister vent solenoid, fuel vapor control valve tube assembly or fuel vapor vent valve assembly). I would start with a fuel cap, but it could be a number of things in the EVAP system. May have to "Smoke test" it to find it.


And

Some vehicles may exhibit a Malfunction Indicator Lamp (MIL) illuminated with Diagnostic Trouble Codes (DTCs) P0442, P0455, P0456,
P0457 or P1442 or a "Check Fuel Cap" Lamp illuminated with DTC P0457 for the Evaporative Emission System. This may be caused by loose or leaking hoses, loose or broken fuel cap, a leak at the top of the fuel filler pipe neck, a faulty purge valve, FTP sensor and etc. Has the vehicle been back up or bottomed out over something that tagged the vapor canistor? I believe that the vapor canistor sets under the vehicle just behind the fuel tank.


Here is a diagram of the F150



Sorry for the long winded post. Good luck.

The cannister and purge valve look fine but they are mounted very low and have been covered with dust and or mud from time to time. I secured a code reader and will read the specific code and post results soon.

Had the very same thing happen on my 2007 Silverado - it's not the gas cap. My codes were P0455 and P0449 Open in Vent Sol - they replaced the vent sol and cleared the codes. It was covered under warranty.

that may fall under emissions related warranty, poss, 80.000 mi

Redfin was that covered under your 100,000 factory warranty or did you have an extended warranty. Right now I have 70,000 miles.

Jimmye123 is correct. Thanks Jimmy - I hadn't remembered that until I got the service ticket out of the glove box again to be sure. It should be covered under the 8/80k Federal Emissions Control System Warranty. Specified major emission control components are covered for the first 8 years or 80,000 miles of vehicle use. According to federal law, an emission control or emission related part, or a specified major emission control component, that fails because of a defect in materials or workmanship, must be repaired or replaced by the vehicle manufacturer (ie, authorized Chevrolet dealer) free of charge as long as the vehicle has not exceeded the Federal Emissions Control System Warranty time or mileage limitations for the failed emissions system part.

Make sure your Chevrolet service people are aware of that. Did either of my codes match yours?

I just yesterday turned 41,000 miles on my 2007 Silverado. It had less than 30,000 when the check engine light occurred.

That is great information I won't hesitate to take it into dealer now. I couldnt get the codes. Apparently when you disconect the battery to clear code it wipes them out, or at least to the cheap code reader I used. Light comes on once a week so Im sure I will be able to read them again soon. And thanks for the quick replies.

glad to help

Light came back on today. Specific Code is (P0121). Dont know if its worth mentioning but both of the last two times the light has come on I was driving down very dusty dirt roads.