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I have a 2011gmc 3500hd with the 6.0 gas engine. Long story short I am trying to reset the fuel composition. I have used 3 different scan tools with no luck. Says alcohol content is. 0.5. I have tried doing the reset right after a fuel up with no luck. I am using premium fuel with no ethanol right now but would like to go back to 10% for the cheaper gas. Thank you. No trouble codes or drivability problems. And the 0.5 is consistent with all scan tool and has not changed at all.
0.5% might be what it resets to, and stays at if there ain't any corn squeezings in the gas. It's not something I'd loose any sleep over if there aren't any driveability problems.
Also FWIW is this happening with 3 unrelated scan tools? Launch, Thinktool and Topdon are same, chinese, software different tablet.......
2 scan tool were launch but different models and snap on solus. I have alldatdiy it says it should reset to 3%. It stays at the .5 regardless of fuel. I've even tried 85% ethanol once got a lean code with that. Yeah not a problem just curious. I've seen a lot about the composition getting stuck high but not stuck low like this. Thanks for the response
Alldata might be wrong but it's interesting that the fuel composition doesn't move. Maybe the truck isn't flex fuel? Window sticker or the RPO label might help there. Or it's possible the truck has a tune on it which has disabled fuel composition learning??
All scenarios are possible. Didn't think about the rpo code it does say fho so only up to 10% but 8th digit in the vin is g I thought that was flex. I bought the truck used so no idea on tuner. But it still should be able to adjust up to the 10% correct even though it's not a flex. That's what I was thinking that something in the pcm is not allowing for adjustment be it a tuner or whatever. I'm just a shade tree mechanic so I don't know alot. Thanks again for the help.
From what I can tell, VIN G on this truck can be either flex or gas. :silly:
If you can get the calibration ID's and CVN's from Mode $09 in Global OBD (all of the scan tools you named will do this), you can check them against GM TIS to see if it's had a tuner installed.
