Hi , Hope everyone is doing well! I have a issue with a code coming up and not sure why - I have a 2016 c7 2 lt - automatic z51 -
I just added a AWE car back touring exhaust , very happy with it ! But the company explains I purchase the brackets to hold the npp actuators open -
I feel shortly after the shop installed those for me a code p26c8 came on , chassis control module -
now the shop says I don’t have a chassis control module , I’m not sure if that’s true -
would any one know if the actuators being help open would cause the code ? I run the exhaust in track mode so they should be open anyway -

not sure what to look for or is there something else wrong ?
any ideas really appreciated!!
thanks

 

There is a chassis control module. The code is just telling the ECM to turn on the CEL. You need a professional scan tool to read the CCM codes, but they are likely related to blocking the NPP valves open.

 

Hi ! Thank you for the reply ! The shop I went to is a performance shop and they haven’t quite deep dived into the code yet , as we just installed the exhaust . So the ccm code is that something they can change or tell the cars computer it’s ok ?
the exhaust did say to install the holders to open the npp because they are no longer used -

or is there something wrong in the install of the openers maybe ?
im not familiar with the ccm

thank you very much

 

Is this what you bought? The "brackets to hold the npp actuators open" are the AFM simulators. They need to be installed to prevent AFM-related codes. Nothing to do with NPP.

 

hi yes that’s what I bought , but I have 4 of those brackets to hold the actuators - I apologize I thought the npp is the name of having the exhaust that opens and closed those parts -

but it seems like since I installed those exhaust that code comes on - as soon as I start the car /
I can clear it but it comes directly back on -

 

As mentioned before that code is a message from the CCM telling the ECM to light the CEL. It doesn't mean there is a direct problem in the CCM, there could be something external to the CCM. Since you just had the exhaust installed, that is the first thing to suspect as a cause. Make sure the AFM valve brackets are installed and that the valves are set properly according to AWE's instructions.

The CCM controls the AFM valves. The non-NPP C7 Stingray models are the only ones that have just AFM valves. The NPP Stingray models have AFM valves ahead of the muffler and exhaust flow control valves in the muffler outlets. The purpose of the AFM valves is to reduce unpleasant noise when the engine is running in 4-cylinder mode. Here is the schematic for the AFM/NPP controls:


Modules Q15A and B are the AFM control valves (the blue markup line goes from the CCM to Q15A. The wiring from the CCM to Q15L and Q15R shown in the schematic doesn't exist on your car.

Could you clarify what was done with the AFM valves and their simulator brackets? Did the shop install the brackets and valves? Did they modify the valves per AWE's installation instructions before installing the valves in the brackets? Did the shop plug the connectors of the wiring harness from the CCM into the valves?

AWE's Valve and Bracket Installation Instructions





Bill

 

thank you very much for all the info , so my car does have 4 actuators , as you mentioned 2 on each side before and after the muffler -
they did all of what you mentioned as far as I know ? But I’m going to ask them and send them the info you provide !! I really appreciate all the help ! Thanks

 

The awe axleback "includes" the afm actuator bracket. Was it missing from the box or did the shop forget to install it? Your afm valve actuators (before the muffler) need to be mounted to the brackets to avoid the cel. Your npp valve actuators (after the mufflers) just have to be taped and tucked up into the chassis with zip ties.

 

hello!
oh I’m sure we put them on all 4 of the actuators -
before and after the mufflers , because I purchased two extra -
so would that be the cause for the code in your opinion ?

Thank you very much for the advice!

 

What code? You need to read the DTCs in the CCM for us to provide a meaningful answer!

 

the code my reader is capable of reading is
p26c8