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Needs some help here guys.
On a long 11 hour trip home, CEL came on. Got Codes P26C8 and P12EF with my code reader. I was able to clear them but they returned about an hour later.
I have AWE track exhaust with the AFM simulators. This happened after I for some reason, which I never do, put it into eco mode (m7 transmission) for only a short time. No problems prior with the exhaust which has been on about two years. Any ideas?
Thanks
Both code descriptions are below…your “code reader” will not be able to read the trouble code stored in your chassis control module…to diagnose the P12EF you will need some electrical skills to check the exhaust flow control valve circuit…open, short to ground or to B+.
Both code descriptions are below…your “code reader” will not be able to read the trouble code stored in your chassis control module…to diagnose the P12EF you will need some electrical skills to check the exhaust flow control valve circuit…open, short to ground or to B+.
Thanks but all that is above my skill set. lol
Was hoping to get an idea of the problem in English! lol
Any way I removed the negative battery terminal, took it out for a spirited drive and the CEL didn't return. I'll just have to keep an eye on it...
P12EF Chevrolet Cylinder Deactivation Exhaust Flow Valve Stuck Closed Bank 1
What it is telling you the left bank 1 valve is stuck closed. Since you are using simulators and there are no mechanical valves present you may just have a bad actuator. Since you went into eco mode the valve would close depending on the system saw and it did not reopen or the actuator is some how is stuck in the simulator.
The P26C8 is there because of the P12EF once the that it is cleared/repaired and you go thur several engine cycles it should go out.
For a M7 the AFM valves are not used in any other chassis mode but Eco.
C7A8 have the same master code P26C8 but with sub code P12FD meaning my passanger side AFM valve stuck open. This will not clear even if you disconnect the battery as the issue will persist after a couple cycles.
looking to replace the actuator. Ordered from gm site and got a quote from the dealer to replace it. I didnt not advise them of the CEL i simply asked them to quote the replacement labor.
Question, once installed, is there a proces you have to do manually to clear it or will it go away on ors own after a couple cycles. Ive read somewhere you have to do the "relearn" process (like tpms i assume) but unsure if it requires a tune if some sort or it will just pick it up. I dont wanna spend hundreds on the actuator and labor only to have a persisting CEL
I guess you noticed you can’t clear these DTC’s !!…in 2010 and fully implemented in 2012 is “Mode 10”…these are permanent codes that can’t be erased unless the car is fixed and has run 3 drive cycles or the monitor has run and shows completed.
C7A8 have the same master code P26C8 but with sub code P12FD meaning my passanger side AFM valve stuck open. This will not clear even if you disconnect the battery as the issue will persist after a couple cycles.
looking to replace the actuator. Ordered from gm site and got a quote from the dealer to replace it. I didnt not advise them of the CEL i simply asked them to quote the replacement labor.
Question, once installed, is there a proces you have to do manually to clear it or will it go away on ors own after a couple cycles. Ive read somewhere you have to do the "relearn" process (like tpms i assume) but unsure if it requires a tune if some sort or it will just pick it up. I dont wanna spend hundreds on the actuator and labor only to have a persisting CEL
thanks!
If the dealer replaces the actuator the Tech should also do a relearn along with verifying the degrees open and closed are within specifications.
Check engine light
