8.1 PTO tables

**Brads_rs** · December 19th, 2013

Hi all, Im looking for a tune file for 2005 8.1 with pto enabled. I downloaded one from tunefiledepot, but cant find any tables in it for pto. Maybe there are none? First time working with PTO stuff. I have a customer who wants to run water pumps with the 8.1 engine and i thought it would be nice to use the PTO function for high idle around 3600 rpm. Any help would be nice.

**Taz** · December 19th, 2013

I have never used this .... however, I believe the PTO high idle circuits are enabled in all 2001 to 2006 8.1L L18 controllers. Wire a momentary switch from C1 (Blue) pin 31 to ground - this is used to activate the PTO functions. The vehicle must be stationary, and in Park (or Neutral). I believe the Cruise Control stalk switches are then used to control the idle speeds .... an internet search may turn up a manual for this.

**Big Mike** · December 19th, 2013

Every 8.1 file I've ever seen has the provision for PTO in the platform configuration set to "yes", but it still needs flashed with a Tech2 to actually enable it. I have the GM document explaining it all if you'd like to see it. Or if you dig around GM's upfitter site it's Bulletin #53 titled "Power take off & High idle".