JP and I have discussed this quite a bit. When he was doing the white LS9 Camaro he had to do all kinds of BS to get it to work. He called GM and got some unclear information and was told PWM is not possible on the GMPP harness kits. This is in contrast to Scot's experience, but Scot's kit is much older.

I suspect at some point GM changed the firmware/OS (pure speculation) to render PWM not functional. JP ended up getting a used E67, refreshing it with a Corvette LS9 OS and was able to make it work.

Hopefully JP jumps in here to clarify, but that's my recollection.

Andrew

Yeah, that's what I read, I was hoping that maybe it was just a Florida problem. :) Trying to make this install as OEM as possible and thought it would be a nice touch.

Donny,

Presumably this is for a customer, in which case I would encourage you to make this work for him/her...It really makes for a much nicer driving experience. It may be a Florida problem, so you should try it out for yourself.

Andrew

Scot's kit is much older? Scot me? What kit is older? My GMPP controller kit? How do I find how old it is?

Yes I'm running the fan through a PWM control box from a GMPP LS3 controller. Friend of mine is also. Had to add some wires to the harness, and reprogram ECM for it.

I recall you saying that your kit is from around 2010...I could be wrong in my recollections...

Mine is from 2008 but I have not tried to implement PWM on my GMPP kit.

Andrew

I bought mine Round 2010/2011 from another member here. It was still new in box, but not sure how long it sat on the shelf.

Can the full OS on the ECM be reprogrammed from HP tuners vs just tuning it?

Andrew, I agree, it's the only way to fly. I just finished a car and we ran the fan PWM, ac pressure sensor and everything, but that was with a Speartech harness and E67.

I just don't want to start from scratch with the rest of the tune if we have to reflash another ecm. Further complicating the situation is fact that this an Erod crate engine and must pass emissions when it lands in California.

While there has been several 'releases' of calibrations for the LS crate engines, the software has remained the same.

So enabling PWM fan control is matter of wiring properly and enabling in calibration.

Dave

Somewhere in this thread is the pinout for the E67 with callout on which spots to add wires & pins to for the PWM functionality. I have the full pinout chart if anyone wants it. I also have a PDF with instructions on how to disassemble the ECM connectors.

Anyone have any luck getting PWM output from an E38 ecu with a camaro OS? No matter what settings I use it will not output a signal. If I use a truck OS I get a PWM signal easily. The truck OS does not see AC pressure. The car OS does. This is why I need to use a car OS. I used an oscilloscope to verify