Originally Posted by
Pulse_GTO
I put together a Lean Cruise and Flex Fuel patch for the 12587603 OS for a P59 PCM. What OS are you using?
I posted it over at pcmhacking and I'll post it here too. According to some testers, this patch keeps cruise control working. Please read below on how it works.
!!! DISCLAIMER !!!
I'M NOT RESPONSIBLE IF FLEX FUEL OR LEAN CRUISE BLOW UP OR MELT YOUR ENGINE. BE SMART, USE YOUR BRAIN AND ASK QUESTIONS IF YOU ARE NOT SURE ABOUT SOMETHING.
FLEX FUEL PATCH - Applying this patch will turn FF on and populate all the necessary parameters with values taken from a P59 2004 Flex Fuel Silverado L59. There are 30+ parameters that need to change for FF to work as the factory intended and they are automatically populated when applying the patch. Will additional tuning be required? Of course. The patch gives you a good starting point.
YOU WILL NEED TO INSTALL AND WIRE IN A GM FLEX FUEL SENSOR BEFORE APPLYING THIS PATCH!!! There are some notes in the patch parameter summary, but it is not by any means a complete write up.
LEAN CRUISE PATCH - Applying this patch will turn on Lean Cruise like in the Holden vehicles and populate all the necessary parameters with values taken from a 2004 5.7L Holden Commodore M6. There are 9 parameters that need to change for Lean Cruise to work and they are automatically populated when applying the patch. Again be smart, use a wideband and verify that the PCM is applying Lean Cruise correctly.
Make sure you do a full flash (Write Entire) of the bin file after applying the Lean Cruise patch.
If you see multiple tables for the same address those are duplicates with either different units on the rows and columns, different units in the parameter or the rows and columns are transposed to make it easier to copy and paste from other sources. No need to change them all, a change in one will be reflected in the others. Regarding table B3639 - Lean Cruise Enleanment, only make changes to the EQ Ratio table, the two other tables, AFR and Lambda, are there only for reference/sanity check. If you make changes to these table you will wind up with garbage data.
If you see any errors, please comment so that I can make any necessary changes.