Stock and Aux Tank cause Evap errors in summer at high Altitude with Ethanol fuel- When do Permenant codes go away

[Romer]

I have gotten several codes this summer. Denver violated an EPA Guideline so they added extra stuff to the fuel besides the Ethanol. The call it more "Reformulated gas". It seems to make my system go crazy on a hot day. Likely overtaxing the carbon filteer isntalled above the tank. It is still the stock one.

When the error happens, the 4LO, Check Engine and traction lights flash on the dash. You can't engage 4LO or likely out of it if you were in 4LO when it happens. Severaal thrfeads out there already on this.

I do have an OBD reader and cleared the codes. However, the Permenant codes remain. Normally I wouldnt care. I know that I will have to emission test in Jan/Feb (every other year) and they likely will fail me if the permenant codes are still there. Lots of time and starts to cycle through for them to go away.

An internet search provides lots of conflicting info like 500 starts or just one normal drive cycle

Anyone know what it takes for the permenant codes to go away?

I plan on not filling the Aux fuel tank in the summer in the future unless going on a trip

Good idea for everyone to get one of the OBD BT reader and a BT app for your phone. If it happened on a wheeling trip, I wouldnt be able to swith to 4LO without one.

The Permenant codes currently showing

 

[Sandroad]

Great question. It’s very entertaining to read all the different opinions on how to clear them. But, seriously, I wonder if Techstream can be used to clear them immediately. Dealers must be able to do that?

 

[bloc]

Are you sure you’ll fail with a permanent code? They should be able to see whether it’s historical or current (or at least techstream and some other apps do), and I can’t see them failing a vehicle which had an issue that had been effectively fixed with the readiness monitors satisfied.

Or are you saying the code is staying in current status and/or your readiness monitors aren’t completing?

 

[TeCKis300]

Those trouble codes are a PITA for the way they affect unrelated functions. Guess the EPA really wants to make sure emissions CELs, aka MOAB CELs (because they commonly come up when offroad crawling into high elevations), won't be ignored.

Looking up the issue, it seems the reformulation should help. Suncor was violating EPA standards by allowing more evaporation pressure (RVP 7.9 psi) than what is allowed (7.8psi) - hence probably why you had more of an issue this summer. The reformulation brought it back down.

RVP is important because it describes how much volatility and off-gassing a fuel formulation has relative to temperature (tested at 100°F). Summer blends have much less RVP. Winter blends can go as high as 15psi RVP, partially to help starting in cold weather.

To your problem - we can't control the fuel formulation (although premium fuels generally have less RVP). Elevation plays a part but can't completely control that. So it's all about heat that's getting into the fuel. Aux tanks, skids, bumpers, can have affects, whether by surface area, trapping heat, or altering airflow under the chassis. There's no single solution and it's a matter of degree.

I have found some degree of mitigation by adding insulation. A recent body lift seems to also have helped.

DIY Fuel Heating/Boiling Mitigation

This thread is not quite a comprehensive fix (yet), but hopefully gets the ball rolling to improve upon fuel venting/boiling in the 200-series. I don't have complete answers and hoping there will be continued contributions by the hive mind. This is one of those issues that may not have a...

forum.ih8mud.com

 

[Romer]

Are you sure you’ll fail with a permanent code? They should be able to see whether it’s historical or current (or at least techstream and some other apps do), and I can’t see them failing a vehicle which had an issue that had been effectively fixed with the readiness monitors satisfied.

Or are you saying the code is staying in current status and/or your readiness monitors aren’t completing?

whether I fail or not isn't specifically key to understanding how to clear Permenant codes

All current codes are cleared. These are Permenant codes set so emissions, new buyers and other folks can tell you had an issue and may have cleared the current codes driving up.

The main difference between OBD temporary codes and OBD permanent codes is how they are cleared:
OBD temporary codes
Also known as Diagnostic Trouble Codes (DTCs), these codes can be cleared using an OBD-II scanner or by disconnecting the vehicle's battery.
OBD permanent codes
Also known as Permanent Diagnostic Trouble Codes (PDTCs), these codes cannot be cleared using an OBD-II scanner or by disconnecting the vehicle's battery. The vehicle will clear the code itself once the issue has been fixed and the vehicle has been driven under different conditions.

It doesn't specify what the different conditions are and that is my question here. It could be different between GM and Toyota or maybe even between modesl in same brand. I don't know

 

[Romer]

Those trouble codes are a PITA for the way they affect unrelated functions. Guess the EPA really wants to make sure emissions CELs, aka MOAB CELs (because they commonly come up when offroad crawling into high elevations), won't be ignored.

Looking up the issue, it seems the reformulation should help. Suncor was violating EPA standards by allowing more evaporation pressure (RVP 7.9 psi) than what is allowed (7.8psi) - hence probably why you had more of an issue this summer. The reformulation brought it back down.

RVP is important because it describes how much volatility and off-gassing a fuel formulation has relative to temperature (tested at 100°F). Summer blends have much less RVP. Winter blends can go as high as 15psi RVP, partially to help starting in cold weather.

To your problem - we can't control the fuel formulation (although premium fuels generally have less RVP). Elevation plays a part but can't completely control that. So it's all about heat that's getting into the fuel. Aux tanks, skids, bumpers, can have affects, whether by surface area, trapping heat, or altering airflow under the chassis. There's no single solution and it's a matter of degree.

I have found some degree of mitigation by adding insulation. A recent body lift seems to also have helped.

DIY Fuel Heating/Boiling Mitigation

This thread is not quite a comprehensive fix (yet), but hopefully gets the ball rolling to improve upon fuel venting/boiling in the 200-series. I don't have complete answers and hoping there will be continued contributions by the hive mind. This is one of those issues that may not have a...

forum.ih8mud.com

Thanks for that. Could be a winter project for me. Wonder if I should replace the canister above the Aux tank at the same time. For now, my mitigation will be to run enough gas in the short term that I can empty the aux tank and leave it empty until next spring or I go on a trip. Not really needed unless traveling and towing.

 

[Fisher23]

From what I have read it is 3 cycles .. AND it can take MONTHS to clear the Evap perm codes.

 

[Zill]

For the permanent codes, if you disconnect the battery and let the system completely discharge, would that fix it?

 

[Romer]

For the permanent codes, if you disconnect the battery and let the system completely discharge, would that fix it?

see post #5 in this thread

 

[Zill]

see post #5 in this thread

What a PITA.

I wonder how the codes are stored without an energy source? Maybe solid state tech?

Looks like they started implementing these in 2010-ish?

It does look like most States still allow you to pass emissions if you have a permanent code, if you drive the car 200 miles AND have 15 warm up cycles without the current code coming back up. The car will the tell the government tester to ignore the PDTC if that’s done.