Check Engine light ...cont.

[ruttinbuc]

Mike, usually a check engine light is not a glitch. There are hundreds of different codes that could set that light off. Chances are if it's not running funny or drinking the gas more than usual it's probably a emission component related issue flagging the light. Most common thing is the vent solenoids sticking on them. There's an updated replacement procedure to change them and run a long 5/8" hose up above the transfer case for the solenoid filter to help it from failing again. Could also be the fuel tank pressure sensor shorted. Those are the two common things.

Thanks Shaun

The light goes away now and then, but I can always count on seeing it again. I don't have any performance or fuel issues except for the normal winter mileage drop. Tire pressure changes and the ever so messed up oxygenated ,10% (more like 20) ethanol retarded gas!

Is the solution something I can take care of myself or do I need to take it to a dealer.. Could it be something as simple as a gas cap change? I hope...:ninja:

[92xj]

Could it be something as simple as a gas cap change? I hope...:ninja:

Yes, a loose gas cap can throw a check engine light on, on some vehicles. Instead of running to the dealership, I would go to a small town shop or a autoparts store. All of the ones around me and when I worked at the shop, would never charge to scan a vehicle real fast to see what codes are throwing the check engine light.

[Shaun_300]

Loose gas cap will throw a check engine light, but usually there's nothing wrong with the cap other than being loose. I'm just going out on a limb saying it's probably the EVAP vent solenoid. Do like Ben said and go have an autoparts store throw a scanner on it for free. If it's P0442, P0446, P0455 or P0449 chances are it's the vent solenoid. On rarer occasions the fuel tank pressure sensor goes crazy causing a P0442 or P0455. But 9 times out of 10 it's the vent solenoid.

Get the code and let me know what it is, if it's something totally different I'll see if it's something else that's common.

[ALAN]

my mom had a explorer check engine light came on so i called her and told her she told me to take it to shop so i did..guy hooked scanner up done his thing didnt say anything walked back to gas cap took it off put it back on told me loose gas cap

[ruttinbuc]

Went and got the code, Shaun. It spit out a P0449 and a P0101 The guy told me to check all my hoses and such from the air filter box.....?

[Shaun_300]

P0449, almost guaranteed it's the vent solenoid. P0101 is a mass air flow sensor code, take your breather tube off the airbox, where the rubber flexible pipe clamps on, spray the heck out of the mass air flow sensor with some brake parts cleaner. Change your air filter if you haven't done so in a while. This code probably wasn't a current code, you'd know it if your MAF was screwy. A quick clean should fix it up, probably just a touch of dust or dirt on the little resistors inside.

Found a pic, unplug the sensor seen in the pic, loosen the clamp you see in the pic and unscrew your 4 airbox screws. Everything will pull out so you can clean it good, replace your air filter if you haven't in the past while.

The MAF sensor will look like this:

Edited December 18, 2010 by Shaun_300
Added info

[LETMGROW]

No doubt you need a new vent solenoid. Gas cap? This is usually wishful thinking. Once in a while somebody leaves one loose and it indeed will turn the MIL lamp on. Seldom is the cap actually bad. We have had a few vehicles that have had a build up of rust on the top of the filler tube causing the rubber O ring on the cap not to seal properly. This is remedied by a cleaning with scotch-Brite and a little elbow grease. I wet the neck with WD-40 to help cut the rust and prevent any chance of creating a spark.

If you don't see a visible crack in the cap's O ring and it tightens down properly, the cap is probably good.

The MAF code could be a dirty wire inside the sensor. Before I removed it I would do a couple things first.

Make sure all clamps are secure and hoses are fitted correctly. A lot of oil change service shops check air filters as part of their service. If you recently had the oil changed by one of these shops you may have a clamp loose allowing air to enter downstream of the sensor.

Another thing to try: With the engine idling, tap on the MAF with a rubber handled screwdriver. If the engine stumbles or stalls you do have a MAF which will fail soon. Otherwise clean it as Shaun suggested.

If the code comes back I would change the MAF sensor pronto. These can be a nightmare for driveability as well as kill gas mileage.

Lynn

[ruttinbuc]

Thanks for all the help Shaun and Lynn. It looks like something I can fix if it ever gets warm enough. I can do the P0101 air cleaner fix pretty easy under the hood. The vent solenoid underneath will take a bit.

What really troubles me is the price for the part from GM compared to Ac/Delco. Rape pure and simple. Another thing is this statement from a car repair forum.

"Chevrolet put this unit under the vehicle I guess so it could collect enough dust to fail after the initial 36 month, 36,000 mile warranty! Course the new part is guaranteed for ONE year so keep all the old parts in case you have another failure in ONE year and you can exchange them for another new one! Not too bad to have a spare! They should have recalled and replaced this unit years ago but who is gonna make them? They make money out of this little defective unit and still have no idea why they went into chapter 11 bankruptcy and are headed for chapter 7 if they fail to get connected to their customers and quality! "

Sort of figured this out on my own after reading page after page of people with the same problems looking for a solution. That writer went on to say that the parts department told him they sell one of those units everyday.

Nothing at all against those who fix these vehicles for a living everyday. I'd be happier knowing that they got their cut from the overpriced parts and all of the labor cost. Another example of getting hit over the head and stealing your wallet. Just sayin'

Thanks again, guys!

.

[LETMGROW]

GM is not the only one

:ban:Ford also mounts these valves under vehicle, Chrysler uses leak detection pumps mounted underneath. Most imports do the same. Especially in the environment we have up here with the snowy roads, ice, sand and salt we have a high failure rate of these parts.

Gm has updated some applications where we plumb a 5/8" hose up to the trans. area and mount a remote filter to send clean air to the valve when it opens.

My own truck I wrapped a piece of cheese cloth around the filter and secured it with a tie strap. I check this each time I change oil. This might not be convenient for the average owner but I have an advantage here.

I don't blame the builder's of the vehicles as much as I blame the greeny who dreamed this idea up in the first place.

It rates right up there with me with the environmentaly friendly gas cans you are forced to buy today

Lynn