Hondata K-Pro (Version 4) with 2005-2006 RSX Adapter Harness
Part Number: K-Pro 05-06 RSX with adapter harness

Hondata K-Pro (Version 4) with 2005-2006 RSX Adapter Harness
    Some images may be for reference only

    Free Shipping
    Inside Continental United States


    Earn 1680 reward points. Learn More

    Will It Fit Your Vehicle?


    Hondata KPro (Version 4) is a fully programmable ECU for 05-06 Acura RSX (DC5). K-Pro is a must have to get maximum performance out of your k-series engine.

    This is a Hondata modified 2002-2004 RSX ECU and an adapter harness for the 05-06 RSX. You are responsible for providing your own 02-04 ECU and 02-04 oxygen sensor. K Series Parts sells a package with a brand new 02-04 Honda ECU and 02-04 Denso O2 sensor: if you do not want to source your own.

    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.

    If you would like to upgrade from a previous k-pro version to version four, it is done directly through Hondata using this form:


    You are responsible for paying for and sending your ECU to Hondata. You can send your ECU as fast as you would like and shipping costs normally start at $10.00 for ground and $60.00+ for next day air. We recommend using an express service (2 day or next day) through FedEx or UPS because they have the least amount of delivery problems, provide proper insurance, and have good package tracking. We recommend that you do not use USPS because of delivery issues. You are not sending your ECU to K Series Parts you will be sending it to Hondata directly and we provide all of the instructions on where it needs to be sent once your order is approved.


    After we approve your order we will send you two emails, one email will be a Hondata form and the other email will be instructions for shipping and what items need to be included. Orders submitted by 3:00pm Mountain Standard Time Monday to Friday are normally approved same day. Orders places after 3:00pm MST or on Saturday and Sunday are processed the next business day.

    Hondata normally reflashes ECU's the same day they receive them but they do get busy and it might take an extra business day. We recommend that you plan on a 3 day total turnaround time from the day that Hondata receives your ECU.

    Return Shipping

    Hondata uses K Series Parts FedEx account to next day air the ECU back to you once the reflash has been installed. This means that you do not have to pay for return shipping. Your ECU will arrive by 3:00pm the day after Hondata completes the reflash installation. Hondata does not provide us with a tracking number or notification when they ship the ECU back to you.

    ECU Serial Number

    The serial number is located on the ECU. Hondata has provided instructions on how to remove the ECU.

    International Customers

    K Series Parts cannot sell K-Pro to customers outside of the United States unless you purchase a brand new ECU or send your ECU to K Series Parts directly. Please contact us first if are not located in the United States.

    Version 4 Enhancements

    Faster and More Powerful: The KPro4 uses a faster processor with more capability than the KPro-III. This allows the KPro4 to perform more tasks without slowing down the ECU, like live tuning, output to a dash, flex fuel and advanced protection. Calibration uploads and datalogging from a laptop are also faster.

    Enhanced On Board Datalogging: The KPro4 has double the datalogging memory (64 MBit) of the KPro-III and can datalog at double the rate (100 Hz), giving an on board recording time of 10 - 220 minutes.

    Faster Uploads: The upload time is 30% faster than the KPro-III, with a typical initial upload time of 7 seconds. Subsequent uploads are also faster, and live tuning can be used for instantaneous updates. Laptop datalogging is also 30% faster than the KPro-III.

    Live Tuning and Autotune: Main tables can be updated in real time, without affecting the operation of the engine. This allows dyno tuning without pausing to upload. Autotune uses live tuning and a laptop to tune fuel tables as you drive.

    Bluetooth: The KPro4 includes Bluetooth for laptop programming/datalogging with a USB cable, and mobile datalogging.

    Ethenol Sensor Input: An ethanol sensor can be directly connected to the KPro4, allowing flex fuel operation, with adjustments to fuel & ignition tables performed automatically based on fuel ethanol content.

    Speed Sensor Input: A speed sensor input can be directly connected to the KPro4 and sent to the ECU. This is configurable to any pulse based sensor and eliminates the need for a stock speed sensor.

    Dash & Datalogging Outputs: The KPro4 has serial output (both TTL & RS232) and CAN output so that a dash can be driven from the KPro. The AiM MXL, Racepak & generic CAN outputs are supported.

    Advanced Protection: Advanced protection options use the KPro4 analog inputs and engine information to intelligently shut down the engine when the conditions might be dangerous to the engine.

    Better Wideband Support: The KPro4 can process a wideband lambda input (either analog or digital) and allow the ECU to run in closed loop from an aftermarket wideband without requiring the stock o2 sensor.

    05-06 RSX K-Pro 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.
    • OBD2 must be disabled to eliminate errors generated by the ECU looking for emissions items that the 05-06 RSX does not have.
    • 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. Read this for more informaiton on the K Series Transmissions.

    Donor ECU

    • The donor ECU is not included and is sold separately. You can supply your own ECU as long as meets the requirements below.
    • 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.


    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.


    • 2005-2006 RSX (manual transmission with adapter harness and modified 02-04 ecu and O2 sensor)


    • Fits inside the ECU
    • Designed and assembled in USA
    • USB connection for speed and compatibility
    • KManager Windows based software for parameter & table editing, calibration uploading and datalogging.
    • Many built in calibrations for common engine combinations
    • Built in datalogging to a laptop
    • On board datalogging memory (2 MB memory, 10-110 minutes datalogging)
    • Adjustment for different sized injectors, with overall fuel trim.
    • Configurable for any MAP sensor (to 5 Bar and above)
    • TPS based table lookup for ITBs
    • Engine protection from over boost and lean protection.
    • Expanded fuel and ignition tables, both in rpm and load, to 60 lbs boost and 11,000 rpm (these are not the upper limits)
    • Launch control with anti-lag
    • Three multi purpose outputs for nitrous control or similar
    • Supports lambda tracing from the stock wideband o2
    • PWM output for boost control

    K-Pro Highlights

    • Base maps are included only for K20A2, K20A3 (RSX Base), K20A3 (Civic SI) and K20A engines.
    • The 2002- CRV ECU (5 speed) (PPA -A0# ECU) can be used.
    • Support for the manual K20A3 engine and the secondary intake runner as used in the base model RSX and CRV.
    • The Japanese PRD and PRC ECU do not support a fuel tank pressure sensor required for some US emissions tests, but will likely pass a tailpipe sniffer test if the catalytic converter is in place.
    • PNF, PPA and PND ECUs for 5 speed transmissions will not operate the reverse lock solenoid on 6 speed transmissions.
    • The K-Pro ECU will not work on Automatic vehicles. Automatic ECUs cannot be converted to manual.
    • To use the K-Pro on a 2005-2006 RSX, an adapter harness is required, an 02-04 specially modified ECU must be modified for used and the primary oxygen sensor from an 03-04 must be used.
    • Turn around time is usually 2 days from the time it is received.
    • From previous ECU's Honda has changed from 2 dimensional tables (engine speed and engine load) to 3 dimensional tables (engine speed, engine load and cam angle). The K-Pro ECU retains these 3 dimensional tables to ensure the engine is running at optimum efficiency and power for every cam angle.
    • The stock JDM and US O2 sensor is wide band and can read from 11.5:1 to 30:1 A/F ratios.
    • Most OBDII features may be disabled for race vehicles.
    • Error codes and the OBDII readiness status may be datalogged.
    • Base tables are supplied for the RSX Type S, RSX Base, Civic SI and Integra Type R engines. These tables have been dyno tuned.
    • No external programmer or other equipment is necessary. Just plug the ECU into a laptop via a USB cable.
    • Tables may be map-traced in real time.
    • The K-Pro ECU is not real-time updateable, however most changes to tables and settings can be uploaded in 1-2 seconds.
    • The K-Pro ECU is a separate product from the s100/s200 line, and will not share the same options (e.g. 3 step) nor software (HondaLogger, RomEditor). All systems are fully programmable by the user. All K-Pro ECU systems include all features (e.g. boost, datalogging).

    Counterfeit warning

    It has come to Hondata's attention that counterfeit KPros, green circuit board Versions 1 and 2, are being sold as new and used. Protect yourself from purchasing a counterfeit K-Pro by checking out this page.

    KManager Software Features

    • Download KManager Software
    • KManager Details
    • High and low speed 16 x 20 ignition and fuel tables for correct VTEC tuning
    • Injector size fuel trim
    • Fuel trim for starting, throttle tip in and individual cylinder trim
    • Rev limiter with fuel cut
    • Launch control with anti-lag
    • Adjustable VTEC window with load and throttle control
    • Adjustable idle speed
    • MAP sensor type and calibration
    • Adjustable boost cut with hot and cold settings
    • Closed loop control
    • Air temperature compensation
    • Fuel and ignition correction based on gear
    • Closed loop
    • Three general purpose outputs for nitrous control, quad boost control or similar
    • On board datalogging trigger conditions


    Honda may not cover mechanical damage to the engine under warranty resulting from exceeding the factory red line. Hondata & Club RSX will not cover any damage as a result of installing this product.


    Brand: Hondata
    Part Number: K-Pro 05-06 RSX with adapter harness
    CARB Approved: No

    Vehicle Fitment

    Acura RSX

    11 reviews for Hondata K-Pro (Version 4) with 2005-2006 RSX Adapter Harness

    5 out of 55 out of 55 out of 55 out of 55 out of 5

    5 out of 5.0

    Add Your Review

    5 out of 55 out of 55 out of 55 out of 55 out of 5

    2/18/2015 by Nolan Grieb


    Easily the best mod I've had so far! All I have is a Sri and Q300 running the cai base map on my 06 type s. All I can say is wow. Throttle response is better, installation was easy enough, and a great increase in hp and tp.

    5 out of 55 out of 55 out of 55 out of 55 out of 5

    6/27/2014 by Michael DiDomizio

    Worth it.

    By bar the best thing i have done for my car so far. Feels like care runs much better and sounds alot meaner. Very easy to use and install

    5 out of 55 out of 55 out of 55 out of 55 out of 5

    6/15/2014 by Joey Ciarlino

    Best Mod

    Love it! Best mod I've done so far, easy install. Can't say enough. Even though all I have it a CAI and a base tune, I can definitely feel an increase in the butt dyno. Highly recommend.

    5 out of 55 out of 55 out of 55 out of 55 out of 5

    12/15/2012 by Allen

    great upgrade if you:

    Need it. You do gain HP of you have it done on a dyno. It also gives you ability to adjust and upgrade as you ad on. But if you are not going too modify, you can get away with the reflash. K-Series is the only way to go.

    5 out of 55 out of 55 out of 55 out of 55 out of 5

    4/15/2010 by Chase

    The best way to make everything work.

    I think if your even looking at this item you should already know what it does. Works like a champ of course and is so easy to install. Do a little research on tuning yourself, meet someone who understands tuning, or just get it dyno tuned. The best ways to make everything work. Super easy to install, just for fun I had my grandma do it, she's 80 and knocked it out like nobodys buisness. Buy it from CLUB RSX!

    5 out of 55 out of 55 out of 55 out of 55 out of 5

    11/19/2009 by Mike S.

    K-Pro 4 Life!!!

    This is so worth the money, I was a bit hesitant about this because of all that comes this. But it is the best mod for the car that you can get the possibility’s are endless. Install was a snap an there are so many people on board that can help you out. I would recommend this to all who want the best out of there mods!!!

    5 out of 55 out of 55 out of 55 out of 55 out of 5

    6/29/2009 by Loren

    Kpro w/ adapter harness

    This has been the best product I have bought for my car period. 5 Stars. Easy to install also.

    5 out of 55 out of 55 out of 55 out of 55 out of 5

    4/2/2009 by yuri

    Fast service

    Great companies to deal with..had my KPRO overnighted at no extra charge from Cali to Hawaii! Car feels alot faster now

    5 out of 55 out of 55 out of 55 out of 55 out of 5

    12/16/2008 by Paulo Ramos

    k pro

    this is what you want if you wanna unlished the power of your k20. the only thing that i can say that i don't like about this ecu, is the fact i got my first speeding ticket in over 5 years. doing 140 on 65 mpg. but seriously this is what you want if your looking to benefit for all the bolt on you have put on.

    5 out of 55 out of 55 out of 55 out of 55 out of 5

    11/4/2008 by STL05RSX-S

    Favorite Mod!

    If you have any thoughts about running serious power then stop thinking and buy this. I have an '05 and its a lot of money to shell out, but well worth it. The capabilities that KPRO has, combined with any mods you have and a good tune just make you fall in love with the car all over again and every time you push the pedal through the floor. As always, CRSX did a great job with the timely shipping.

    5 out of 55 out of 55 out of 55 out of 55 out of 5

    9/2/2008 by Austin Drobnica


    Customer service at CRSX is awesome. Going through them to purchase a K-Pro is a very good idea, and a safe one.