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Ok... I'm not officially stumped.
1 The fuse is ok. I tried a new one
2. I went into the infotainment system asn Restored all the factory settings. Then tried the Exhaust settings..... No luck.
3. Sheeze...now what??
Id unplug and remove one of the motors and try to hot wire to see if it will move.
If the motors are moving, perhaps next try to see if the proper voltages are coming to it at the connector, most likely nothing is still getting the power to that area for reason.
if so you are looking at either the connector or wiring going to it OR possible tuning of the ecu overriding it perhaps??
Id unplug and remove one of the motors and try to hot wire to see if it will move.
If the motors are moving, perhaps next try to see if the proper voltages are coming to it at the connector, most likely nothing is still getting the power to that area for reason.
if so you are looking at either the connector or wiring going to it OR possible tuning of the ecu overriding it perhaps??
I could be having halucinations but I think I remember the signal to open and close the valves is not a straight 12v. I think it is an encoded pulsed 5v signal or some other wierd crap that is used to torment us users when we try to work on the cars ourselves.
Yep 100% accurate that it's a pulsed signal. See attached wire diagram and you can see the little pulse symbols for the AFM and NPP valves coming out of the chassis control module pins 35 and 34 respectively. Check your connectors X350 and X311. That's where the pulsed signal goes through the connectors. Maybe they are loose. Or possibly that ground G401 on the exhaust flow (NPP) control valves is bad. Or no 12V on pin 4 of the exhaust flow control valves.
Well, things just got more interesitng. I bought the car form a dealer in CT. Did the deal online, went up to pick it up. I put it on my car trailer and took it home. The Car had a Clean CARFAX and it sull had 1 month left on the CPO. i did not get it up on a lift until yesterday. Its' on jack stands as we speak.
Low and belhold... That car has long Tube headers w/ cats and a X-pipe feeding into Stock cat backs. So, it may have an aftermarket tune after all . How do I know? Ideas?
Since it has headers it is tuned. Probably sounds really good too.
It does sound good... I'm surprised that the car was "CPO'ed" with that set up. So much for that.
So, how do i find out how the the ECU was tuned? I'd like to know if it's with in my comfort zone.
It does sound good... I'm surprised that the car was "CPO'ed" with that set up. So much for that.
So, how do i find out how the the ECU was tuned? I'd like to know if it's with in my comfort zone.
Any one know a good shop near Baltimore ?
You need to look for someone that has HP Tuners. You can use that to download your calibration and CCM information which is where the NPP programming resides. You'll also need a stock file for your model year to compare against.
Unless I missed it, you should reach in with channel locks and make sure you can manually move the valves. I have had 3 in two years Freeze up. When pulled out, soaked in lube and worked with pry bar got them free again, then actuators worked fine.
I have 2 mods on my car....off road x pipe and afe CAI. Ive noticed with the increased air flow from the CAI ....the car is louder all the time , seems like the NPP exhaust doesnt have much effect now...prior to CAI it had a huge difference. Ty all for the information here...im gonna have to check the actual tips
instead of pulling the fuse to stay open why wouldn’t you just set to off in the engine sound management options?
That works for M7 cars. However, the A8 cars have AFM active all of the time unless the transmission is switched into manual mode. When AFM switches the engine to 4-cylinder mode the Chassis Control Module will close the NPP valves as GM determined the engine sound during 4-cylinder operation was objectionable. With an M7 car, AFM is only active when the Drive Mode is set to ECO.
If you have an M7 set Sound Management to Track and the Drive Mode to ECO then drive the car around in 4th gear at about 50 mph. To activate the valves lift off the throttle slightly and AFM will switch to 4-cylinder mode, after driving with a light throttle pedal to keep the engine in 4-cylinder mode accelerate moderately and you will hear the valves open.
