Since I melted both the AFM Exhaust Valves last month at Palmer, I had them replaced under warranty (19 GS w/Auto).

Yesterday temps were 92* high and so was humidity at Thompson.
Exhaust valves behaved for what I thought was the entire day.
However as I was leaving the track I got a MIL, this time there was no mechanical noise like last time.

Checked the codes and got "P12F2" (Cylinder Deactivation Exhaust Flow Valve Actuator Performance (Bank 1))...WTF
I have no idea what that means of if it is an indicator to a pending failure.
I'm hoping someone here knows what its about?

I had considered just tuning out the valves and being done with it since I run a Range AFM Eliminator full time, but I got spooked after several people told me that if there is any powertrain warranty work needed GM gets a copy of the PCM code to insure there is no monkeying around.

These valves make me uncomfortable taking the car to the track, it's not worth the aggravation.
Can I remove these actuators from the Valve and tie them off or space them away from the valve away from the heat.
I have a quickjack, is it something I can do in the garage?

Any input is appreciated

 

How-To: Eliminate AFM actuator melting issue for aggressive/track driving: link. After getting them replaced once more time under warranty, you can do this mod. I've run my car almost exclusively at the track, and never had any issue with this mod.

 

I purchased a Z06 exhaust for my GS and simply zip tied the actuators out of the way. A QuickJack will get your car high enough to swap out the exhaust. You can also add heat shield on the piping at this point as well. I did all this and no codes and trans temp dropped another 10 degrees or so. Doesnt go above 200.

 

read this thread for how to tune this out, I does work although you will note that I had to change some of the settings to insure no MIL on my car (almost at the last of the thread
https://www.corvetteforum.com/forums/c7-tech-performance/4082021-how-to-disable-afm-exhaust-valve-actuators-with-hp-tuners.html

 

I have a 17GS and also run at Thompson. I have replaced the exhaust actuator 4X and the most recent was with a "redesigned" part. The CEL just went on with code P12FO, and the valve is rattling when the car goes to 4 cylinders, so it is back to go. Another bad design on the GS! If you find a good place to get the work done please let me know. Dale Magee

 

I'm newly registered into this forum and I greatly appreciate the info I'd already found here as a guest regarding AFM exhaust valve actuator failures! But I still have a couple questions (and background comments to offer before anyone replies). Background: Please bear in mind that (1) I'm a bit too old and too new to this CF to understand all the acronyms and electronic technology, (2) I do not want to risk voiding the power train warranty, (3) In 1985 I quit instructing in HPDEs and competing in SCCA, but now 20+ aggressive HPDE track days per year are sufficiently satisfying. Therefore my 3-in-1 daily driver / track car / SUV is a 2019 Grand Sport coupe (with A8 trans due to traffic).
Questions: (1) After the AFM actuators have "failed" (and upon cruising away from the track in 'D'/ V4) it sounds like they are able to partially close the valves but then they slam open a couple times per second, producing loud metallic clatter. Is that always the symptom, (my low-tech diagnostic)?
(2) If that clattering abuse of the butterfly valves is promptly prevented by driving in 'M', why would dealers want to replace the complete muffler assys instead of just the $150ea actuators #84560761? [Dealer said- "Because the pipes have now been wrapped with insulation there is no warranty coverage for this nearly $4,000 R&R"].
(3) Does anybody see significant problems with the following solution plan which hopefully doesn't put the power train warranty at risk? I would have a race prep shop remove the failed actuators, attach AWE's "Simulator" plates (their #1310-11030) to new out-of-the-box actuators (GM#84560761), and tie them up away from the exhaust pipes. Then I'll ask a Chevy dealer to make the car 'learn' the AWE Simulator controlled strokes of the new actuators, and clear the fault codes CEL etc.
It's great to be tracking again after 6 months of Covid cancellations! At least it postponed the accumulation of AFM frustration! Stay well.

 

Yes that will work to perfection.

 

But what about the warranty side of it??

 

I went with the AWE Simulators and spacers

You may be able to put the actuators in to "Learn" them and then mount them remotely, however...
If you have a dead battery or disconnect it for any reason, you have to go back in and relearn them - big hassle
The AWEs will provide the stops allowing the actuators to relearn with no intervention


I used the AWE simulators AND spaced them out 1/2" with spacers and screws from McMaster Carr. I wasn't comfortable tie wrapping the actuators to something
The actuator doesn't drive the valve any more, the valve is sprung open, there is no direct contact with the hot Valve stem and the added air gap helps prevent the housing from hitting the melting point.
I have a Range so I have no need to close the valves

One thing I noticed...the new actuators have longer mounting bosses, perhaps GM did this to increase the air gap because of the problem.
When you install the AWEs they may not line up well with the actuator drive plate, you'll have to deform the tabs on the AWE so they engage without binding.

I'm pretty confident that this 3rd time will be the end of it