E38 Fan controls (break points)

[Brads_rs]

Does anyone have/know of the break points for the fan in the E38 ECM? Specifically for 2009 chevy van 4.8 base tune.

I think this is what they are but not sure

Fan 1 on @ 44%
Fan 1 off @ 40%
Fan 2 on @ 90%
Fan 2 off @ 85%

Thanks in advance

[ScarabEpic22]

It's an absolute, but if you're close it will work just fine. Those look in the ballpark though. Try it out and it should kick the fans on at the temp breakpoints you specify. Fan #2 might be tougher, might have to drop the temp enabler to test it.

[Brads_rs]

Thanks for the quick reply. Forgive me if i ask some dumb questions but I'm new to E38 programming. If I set these in G0901 the fan should come on at spec temp? For example say at 200 degrees F, I set it at 44% fan power and have G0927 set to discrete it should command the fan relay on.

I was looking at other post and reading something about a cax file needed to turn fans on and off with spec temp.

[ScarabEpic22]

If the base file does not already have efans setup properly, you cannot enable them with just the parameters EFILive has publicly available. You need to change a few more things in other parameters and tables that EFILive does not expose. You need to build a .cax file to map these tables, have someone who has mapped them perform the updates, or use a competitors product. If you're looking to do 1 vehicle/ECM, there are some guys on here who may help you out. When I installed efans in my TBSS, the vendor who I purchased the wiring harness from provides a "shell" EFILive tune that has the necessary efan changes made and then I scripted my actual tune over the top of that base file.