Permanent Code problem

[bad383ta]

I recently had a friends 2010 Camaro SS come over with no check engine light and no current or pending codes, However it has permanent codes for P0420 and P0430. These permanent codes are form being former current codes that have been cleared but not run and passed after being set. The car was tuned after the codes where cleared and has not had a MIL and the Converter monitor is set and passed, however it still wont pass NY inspection because of these permanent codes that are set. They are not current codes and don't show up with HP tuners., they are not pending codes but former codes stored waiting to run. Even reflashing in a stock calibration wont remove these permanent codes, they are there until they run and pass the code, however the codes will fail everytime because of the highflow cats. The converter monitor is enabled and cat codes have ses disabled and code set to no error reported, converter monitor is set to pass asap with no current or pending codes but the permanent history codes still keep and wont pass inspection. Any help would be appreciated on how to remove permanent codes.

Thank You
Bad383TA

[bad383ta]

Someone must have an idea. I just went out and checked my personal 2011 Camaro SS Drag Car. I have no check engine light and no current or pending codes. However in permanent code history I have lots of codes stored. These are all codes that have come up in the past and I have deleted in the calibration or have not run them. How do I clear the permanent codes from the history. Writing the ECM clears all other codes bu these still exist.

Bad383TA

[2xLS1]

I've been doing this a while and have never heard of permanent codes.

[WS6HUMMER]

I came across this yesterday too, is there any explanation for this?

[schpenxel]

For what codes? What are the details in your case?

[erick_e]

There is a pretty good article explaining permanent code here.

http://www.autoserviceworld.com/feat...ermanent-dtcs/

[WS6HUMMER]

For what codes? What are the details in your case?

The P0420 & 430. Tuned them out "no error reported" but the codes keep coming back and say they are permanent.

[WS6HUMMER]

There is a pretty good article explaining permanent code here.

http://www.autoserviceworld.com/feat...ermanent-dtcs/

Makes sense, thanks for the link. I am working on an 09 too. I guess it won't hurt anything wit those permanent codes since I have COT turned off.

[schpenxel]

AH that sucks. There has got to be a way to reset those things somehow. Have you tried a write entire?

[WS6HUMMER]

AH that sucks. There has got to be a way to reset those things somehow. Have you tried a write entire?

No I haven't but that's a good idea, I may try that.

[APS]

In for updates.

[RoverWorks]

Any updates on this?
I have a 2011 Yukon doner with a permanent P0442. No pending, no current DTCs. P0442 set to not reported. 20+ drive cycles on it. All 8 monitors ready. Can't clear the permanent. Tried the UTDP several times.

[WS6HUMMER]

Any updates on this?
I have a 2011 Yukon doner with a permanent P0442. No pending, no current DTCs. P0442 set to not reported. 20+ drive cycles on it. All 8 monitors ready. Can't clear the permanent. Tried the UTDP several times.

I have the same issue with an 11 Silverado. EFI live and my Autel shop scanner doesn't see the code. Only HPT sees the code.

[RoverWorks]

I checked this with an Actron, HPT, and Tech2. All report this P0442 dtc.
HPT, Actron shows as permanent.
Tech2 shows up under I/M DTCs.

[Blue-Z]

Any updates on this? Ran into this problem today and not sure how to solve it.. Thanks

[JBZ]

Just a thought but check out post 117 in this thread, these are some parameters that i dont have and you guys may not either. You may be able to raise/lower these thresholds and get rid of this permanent problem? Although i dont have the problem with off road exhaust.

http://www.hptuners.com/forum/showth...-Headers/page6

Heres a screenshot of those parameters

[det]

Have the same issue with my 2015 truck. Has anyone been able to get the codes to clear without cats?

[IARLLC]

If memory serves (and it usually does not) permanent codes have to be proven fixed for quite a while (maybe 255 start-ups) before they disappear from memory. What does this mean for us? I think it means that we need to turn off those cat/emission related codes before they occur. Once the ones that are considered more serious occur they become permanent until proven fixed.

So if you already have a permanent cat code or other.....maybe you have to reinstall cats temporarily until it is cleared then turn the codes to "not reported" before removing again.

[APS]

I do a lot of these for a commercial entity. I always turn the tests and the codes off prior to all service work performed.

I have yet to attempt flashing the vehicle with TIS module replacement selection to attempt resolving this.

I have flashed a Ford ecoboost after the fact with permanent codes stored (that I left on because they failed to tell me all that was removed) with FMP on "module replacement" selected. I then flashed the tune file back into it with the tests and codes shut off and it worked. The truck now does not show any permanent codes.

I will try the TIS method on GMs the next time I have one here with permanent code issues.

[mourat]

I turned off the checks as suggested by JBZ and they went away just now