In the past, the CEL came on maybe twice, and we fooled w/ gas cap and within a day, light went off. Looks like it wants to stay on tho not blinking. It came on after COSTCO pumps were under too much pressure or something, and gas would not go in the 3/4 empty tank. We went to a Shell station and it looked like we were gonna have same issue (pump stops almost as soon as you pull trigger to start), but it started pumping and filled tank. Noticed CEL on next trip. Have filled it normally once since, but lite stays on. Running smooth, otherwise. 1) Are there any unique notices a 6.0L "05 Chevy would give at 42.5k mi?2) After gas caps, what is a common cause of CEL?3) If Autozone lot looks too small or they no longer scan vehicles, which of these scanners would you recommend:http://www.autozone.com/test-scan-and-specialty-tools/code-reader/actron-pocketscan-code-reader/603853_0_0/http://www.harborfreight.com/automotive-motorcycle/diagnostics/can-obdii-code-reader-with-multilingual-menu-98570.htmlThanks for your thoughts.

There are dozens of things that can make the CEL come on. If it's an ongoing problem then buy a cheap code reader so you can see what it actually is.

Not sure of the HF unit but I purchased mine around 100 dollars. You can remove battery for an hour or if it's GM try turning on key to on, not start, pump accelerator three times to floor slowly then turn key off and remove from lock. Wait a few minutes then restart and check. This will remove annoying servicereminders and has removed CEL on my diesel pick-up. Sometimes CEL needs to run through cycles. Maybe 4 or 5. A cycle is normal use like running errands. The computer needs to reset and then all should be fine. You may just have a bad fuel cap. Remove and replace a few times. A meter is the best way to go. Once you have the code you can look it up online and see the problem. Everyone should have one to keep the repairman honest.If you can plug in a printer, you can plug in a code checker. They also have nice features to read as you are driving. I found my sweet spot for fuel economydriving my rig from Minn to Cal after I purchased it and overall just a handy tool to own.

Autozone (and probably some other auto parts places) will still scan for free. It shouldn't be too hard to find one you can finagle parking at.As Scott said, there are a vast number of things that can cause a CEL. It basically just means that the engine computer found something amiss somewhere. Reading and interpreting the code is, of course, the best first step towards diagnosis of the underlying problem.Since you had difficulty pumping gas, I would inspect the tank vent line. Maybe it's pinched or cracked or sagging or something along those lines. I think it generally is a smaller hose routed along with the gas tank fill hose. Some problems with it may not cause the CEL, but still affect the tank filling.

All kinds of sensors will make the cel go on. Best bet is to get it scanned. Most auto parts stores will do it for free. Just beware they are sometimes it geniuses when it comes to using the reader/scanner. I had one tell me the computer module was bad after scanning. I bought an Actron scanner and it turned out the O2 sensor was bad. Replaced it. Reset the code and it's been fine for more than 5000 miles now.

Thanks for tips. It has 2 trips = 300 mi since CEL came on. Friend took gas cap fat o-ring off 80 mi ago and rubbed it w/ some pool 'n spa gasket stuff - feels pliable.I had it run rough once when changing batt as comp reset. That spooked ,me enough not to do it again unless have to.The key and 3 pumps has worked on oil service lite, not sure 'bout CEL. I will likely want to know what error I have if CEL STAYS ON.Might give one more 100+ mi trip before getting a gauge. I cannot find where the OBD2 receptacle is on the '05 Chevy.

CEL After Failed COSTCO fill + OBD II Scan | Good Sam Community

Dakzuki
Explorer
Mar 18, 2015
Buy a Scanguage and mount it in your RV. It is very useful beyond just reading codes.

LINK
burlmart
Explorer
Mar 18, 2015
just to update: after a 160 mi round trip, no CEL.
burlmart
Explorer
Feb 19, 2015
a short 35 mi round trip to cracker barrel to eat and generate a doggie bag for pups left guarding the rv. all seems fine and no CEL it was a short run, i know, but here's hoping.
turbojimmy
Explorer
Feb 13, 2015
The EVAP code may come back once the monitor is ready. That's the gas cap related code. The other is likely a bad O2 sensor.
burlmart
Explorer
Feb 13, 2015
DTC P0053 HO2S BANK1 SEN1 HEATER RESISTANCE

Also 1 incomplete monitor, EVAP

I cleared the codes and restarted and CEL was off w/ no codes

Just drive a while to see if it stays clear?

(Gene, I did what you said and called autozone and got actrom CP9125 ($60) easy to see and use. I clean forgot about O'Reilley's and AdvancedAuto.)
Gene_in_NE
Explorer II
Feb 12, 2015
burlmart wrote:
HF say they rarely have the simple reader, snd the next one up is complicated and NOT small print, so may have to look for simple code reader w/ big print at autozone or _suggestions?_

might be worthtrying the android gadget thru amazon, Martha would read it on her smartphone getting
If I were in your situation, I would let my fingers do the walking and call O'Reilly's, NAPA, Advance Auto, CarQuest, or Midas and see whether they would read your OBD port for you. Our O'Reilly's and Advance Auto will do so expecting you will buy the replacement part from them.

Then you might have to go to something like this http://www.obd-codes.com/trouble_codes/ to see if the code is specific enough.

Chances are you will get something like PO440 that is not specific enough "Evaporative Emission Control System Malfunction".

Most mechanics will just tell you the gas cap was loose, and they will clear the code. That code will not reappear unless you have a bad gas cap.
burlmart
Explorer
Feb 12, 2015
HF say they rarely have the simple reader, snd the next one up is complicated and NOT small print, so may have to look for simple code reader w/ big print at autozone or _suggestions?_

might be worthtrying the android gadget thru amazon, Martha would read it on her smartphone getting
burlmart
Explorer
Feb 11, 2015
maybe it's HF tomorrow, anyway. am getting restless to know what codes i have. shouldn't be too hard to get code interpretations for the 6.0L Chevy. if i have an issue, i should get at it before dogs' next state park.
j-d
Explorer II
Feb 11, 2015
The ones Michael referenced above look like this one
from Amazon

The previous "ELM" unit that looked like this

is the one that DID work on the two newer cars but not on the two "older" Fords.

From reviews, it seems that a given form factor of OBD2 interface can have good or not so good electronics inside.

If you use an Android device, you do NOT have to use the mini-CD that the device comes with. That contains the PC (presumably Windows) software.
jfkmk
Explorer
Feb 11, 2015
klutchdust wrote:
mgirardo wrote:
If you have a smartphone, the ODB2 bluetooth transmitter and the Torque app are great. I bought this transmitter and use the free version of Torque. When I bought transmitter it had free shipping, so for $10, I got a code reader, but so much more.

Torque reads codes and clears them and as was mentioned it can give you detailed info about codes if you have access to the internet. What's really great about it is that it also lets you monitor all sorts of vehicle data like Acceleration, Coolant temps, engine load, fuel pressure, intake air temp, mpg, etc., etc., etc. The free version offers close to 50 different sensors that it can monitor.

-Michael

Just ordered 3. One for each of my vehicles. Great idea.

Not sure if it was mentioned, but the torque app does not work with the iPhone. There are other apps that will, but not torque.

The elm transmitters are sometimes******and work only part of the time. The one I ordered from Amazon actually mailed from China (no surprise). The cd that came with the device came equipped with a virus and the manual was so poorly written it was comical. Not only that, but the manual had some kind of pet trial software watermark on each page.

The elm transmitter worked exactly twice before it wouldn't work again. I bought my actron AFTER purchasing the elm and iPhone app.

Oh, by the way, you can't turn the elm device off, you have to unplug it. I'm not sure what the draw is, whether it is enough to kill the battery over time, but I'd unplug it.

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CEL After Failed COSTCO fill + OBD II Scan

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