mallett435

Dealer replaced my AFM valves due to CEL. They have had my car for nearly two weeks trying to get the AFM valves to relearn.

Stock tune and they have replaced the CCM and it still didn't help. I do have a Borla S type NPP cat back.

Two questions. Any suggestions on how to get the relearn to complete? My understanding is that it's a 2 minute procedure. I don't get it...New CCM and new valves.

What are the issues with driving the car if they don't 'relearn'? Tech said there is no CEL now. Do they just constantly open and close?

Chets LS3

I'm not aware of a relearn. You should be able to plug any afm or npp valve into that plug and be good to go.

mallett435

That's what I thought, but apparently it's a real requirement. Here is a quote from a forum member on another thread. "I'd prefer to avoid these issues entirely and skip a dealer visit for an AFM relearn procedure."

I just don't know what happens if they don't relearn. Dealer is getting GM involved now. I'm guessing they will say aftermarket catback, so they won't have to deal with it. Then, what issues will I have to deal with especially that they said the CEL is gone.

Chets LS3

I've did some extensive testing with the afm and npp valves as of lately. I'm confident these do not need a relearn. If both of you and the other guy are having issues with aftermarket exhaust, I would lean towards the spring is having issues in the aftermarket exhaust

djnice

Here is something from another thread that might be applicable to your problem.

Stingray Al

Call Borla, and have them send you new left and right pipes. I had my car at the dealer several times when I put the Borla NPP exhaust on, because I kept on throwing a code. The remedy was new pipes from Borla. I installed the new pipes and the codes went away

mallett435

Great advice! Borla is sending me new pipes this week. Bummer the bumper and mufflers have to come out just to replace the over the axle pipes. Do you recall what codes your were getting before you installed the new pipes? That would really be helpful. Thanks!

X25

Back when I removed the bumper and mufflers to cut out AFM valves, I forgot to reconnect the camera harness, so I had to do it all over again! It was a tough day : )

Do the Borla pipes have flaps inside then, or do they just have a spring to satisfy the AFM system?

mallett435

Borla recommended I try with flaps first (newer version than I have now). They do have pipes with simulators only. Apparently, with superchargers, they recommend simulators only. Borla rep believes u can slide the pipes out without removing the entire cat back and bumper. I'm haven't looked at it close enough, but dealer tech said the opposite.

American Heritage

We have seen a few aftermarket C7 system that had some issues right out of the box regarding the valves/actuators.

You have to remove the bumper and cat back.

Stingray Al

Without a doubt, the bumper will need to come off.

Is Borla now making a pipe with no valves ?

The reason I ask is that I can hear the valves going from v4 to v8 mode. They make a slight metallic "clink" sound.

mallett435

Yes, they have an option to order with NPP valves and AFM simulators. Or, no NPP and AFM simulators. This may be an option instead of cutting them out.

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djnice

I would think the AFM simulator with the actuator installed on the exhaust pipe could still overheat in track conditions and fail. It would be better to relocate the actuator and simulator away from the exhaust if possible.

mallett435

Any new location will trigger the CEL. That's why some of the guy who cut out the valves with straight pipes put the electronics in the same location for the CCM check during startup for the AFMs to not throw a CEL.

I will have the new Borla over the axle pipes tomorrow, so hopefully AFMs will relearn after install. I'm curious if this fixes the CELs of P12F1 and P12FE.

mallett435

New Borla over the axle pipes with valves didn't help. Same CEL code! Dealer installed my factory npp cat back and relearn took 60 seconds. Really disappointed that you can't run an aftermarket cat back system.

People will say their aftermarket cat back system will not cause CEL, but once you have the AFMs fail, good luck with the relearn. I drove 1k+ miles with no CEL until failed AFM actuators threw codes. Grrr!