This is a Hondata modified 2002-2004 RSX ECU and an adapter harness for the 05-06 RSX
Hondata makes hardware modifications to the 2002-2004 ECU enable it to work with the different sensors and actuators found on the 2005-2006 ECU. After these modifications the ECU will not function correctly on a 2002-2004 RSX.
Hondata only sells adapter harness with the modified ECU. An unmodified 02-04 ECU with adapter harness (with or without KPro) will not work on a 05-06 RSX without the internal ECU modifications performed by Hondata.
Warning
Within USA this product is legal only for racing vehicles which may never be used upon a highway.
Pricing
   Price
   Description
   $250
   Upgrade an already K-Pro'd ecu for use in an 05-06 RSX (includes adapter harness and ECU modification)
   $845
   K-Pro for 2005-2006 RSX includes adapter harness (user supplied 02-04 ECU)
   $1740
   K-Pro for 2005-2006 RSX includes adapter harness (with new 02-04 PRB ECU)
Compatibility
The 05-06 K-Pro is only certified to work in an 05/06 RSX. Engine swaps using an 05-06 RSX engine and gearbox into another chassis are not supported with the 05/06 K-Pro and adapter harness. The correct method is here: Hyperlink to:http://www.hondata.com/techk20transmissions.html
Application Notes
An primary oxygen sensor from the 02-04 RSX or 02-05 Civic Si must be used.  The 05-06 RSX O2 sensor will not work.
Some sensors must be disabled to eliminate errors generated by the ECU.
The speed sensor spins about 100 times faster on the 05/06 RSX gearbox as compared to the 02-04 RSX. Above 65-70 MPH cruise control may not function smoothly and may cancel from time to time. Also see Tech - K20 Transmissions
Which Donor  ECU can I use?
Only the following ECUs can be used.
2002-2004 RSX Type S (PRB A03-A08, PRB-305 ECU).  Should be used for a Type S
2002-2004 RSX (Base 5 speed) (PND -A0# ECU) Should be used for a Base
The stock 2005-2006 ECU part number PRB-A13 through PRB-A16 has a different microprocessor and cannot have a K-Pro installed.
Adapter Harnesses
These are the only harnesses that are guaranteed to work with the 05/06 K-Pro. These adapter harnesses are sold only with an 05-06 RSX-K-Pro.
 
Identification:

 - Blue Wire
 - Sticker stating 05/06 Adapter (some adapters may not have stickers)
 - Three white plugs or
 - Two white plugs and a grey plug (from about June 2007)

If you are are having problems you may have a counterfeit adapter harness.  To verify if you have a genuine adapter harness, contact Hondata with the serial number of your K-Pro.