Reflash - Acura RDX


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Hondata, Inc.
2840 Columbia St
Torrance, CA 90503


  • Acura RDX ECU part numbers 37820-RWC-A55 through 37820-RWC-A74 (2007-2011)


  • K23A1-RDX ECU flash program 7200 rpm REV limit - $295

This upgrade information form must be sent if you wish to reflash your stock ECU. 

Hondata does not sell direct - all sales and payment must be conducted through Hondata dealers

Power gains

This reflash was tested on a mechanically stock 2007 RDX. This is a must have upgrade.  Power was gained everywhere, from a strong increase in low end torque to a good increase in top end power above 5500 RPM.

  • Rev limiter raised to 7200 rpm. (sportshift mode only)
  • 10-20 Hp gain everywhere - 26 Hp at peak.
  • 33 ft lb torque at 3300 rpm

Click picture to enlarge

RDX Boost changes

In stock form, the RDX runs 13-14 psi of boost until 4500 RPM, decreasing to 8 psi at 6500 RPM.

Hondata raises the boost level about 1-1.5 psi under 4500 RPM and raises the boost level 3.5-4 psi at redline. As a result the turbo spools faster at lower RPM leading to better off the line performance.

Tuning and performance notes:

The Hondata reflash raises the boost a little, advances the ignition a little and leans the mixture a little. Reflash owners have reported an improvement in fuel economy, but this has not been tested.

The RDX is very sensitive to fuel quality. You must always run the highest quality fuel.  The ECU is constantly monitoring knock and will advance or retard the ignition to suit. Poor fuel, hot intake temperatures, hard loading on a dyno, and high speed running can cause knock. As a result the ECU will retard timing (and reduce the power) until conditions improve.

RDX owners in states that run higher octane than the 91 found in California may well see more performance than shown here.

If you are dyno testing it is unlikely you will get enough air across the intercooler. If the air gets too hot the ECU will retard the ignition, in addition to retarding the ignition from any knock. Reset the ECU by unplugging it for 30 seconds to reset the knock learning.

The increased rev limit only functions in Sportshift mode.

Testing was done on the Church Automotive Dynapack 4 wheel drive dyno.

How will the reflash work with modifications?

At the time of writing there were no intakes available for the RDX. Air fuel ratio is largely determined by the mass air flow sensor located in the intake. Any intake which does not alter the pipe diameter surrounding the mass air flow sensor (and thus the air fuel ratio) should work fine.

The reflash will work safely with an exhaust system.

How do I get the reflash?

You will need to remove the ECU and send it to Hondata through a dealer . Unlike reflashes for other Honda models you will not need to send the key and immobilizer; just the ECU. Fill out this form and contact a Hondata dealer. Hondata does not sell direct. All ECUs must be sent to Hondata for reprogramming. No Hondata dealer has the equipment to reprogram this ECU.

How do I remove my ECU?

The ECU is located on the inner fender beside the air box. Unclip the three wiring connectors. They are released from underneath the plug. You will need a 10mm socket to remove the bolts holding the ecu in.

ECU location:


For further identification, see the ECU picture at the top of this page.

How long does it take to get my ECU back?

Turnaround is 1-2 business days. If the ECU arrives in the morning it is almost always sent out the same day. ECUs arriving mid to late afternoon ship the next day.

Can I send in a new or used ECU?

Neither a new or used ECU will function with your car until the immobilizer system has been programmed to match your keys. This is something only an Acura dealer can do. A new ECU will also require a VIN number to be programmed into it. Again this is a job for your Acura dealer.

What if Honda comes out with an ECU software upgrade?

If a dealer erases your ECU and installs a newer Honda program, you may send your ECU to Hondata to restore the program.  Hondata charges $75 which includes overnight shipping and handling for any program upgrade.

Will this affect my warranty?

Any increase in RPM limit is at your own risk. If you suffer engine damage that is related to excessive revs Honda / Acura will not cover your warranty.

With regard to aftermarket parts, the law is that warranty coverage cannot be denied simply because such parts are present on the vehicle, or have been used. For more details read the K series FAQ.

Customer review

Review by Turbo & High-Tech Performance Magazine

Review by Import Tuner Magazine

Hondata RDX Reflash Review

Turbo cars have always been great for tweaking a bit more horsepower and torque from the factory. Enthusiasts with Audis, Subarus, BMWs, Porsche, Mercedes etc. have long been able to purchase ECU software upgrades to increase their car’s performance.

When Acura released the RDX, I was confident that the leader in Honda tuning technology, Hondata, would eventually release an RDX specific reflash. Hondata recently sent me a reflashed ECU to try in an otherwise stock RDX.

Installation of the ECU is very straightforward; a few 10mm bolts, a plastic cover and some connectors. The swap took me 10 minutes and I’m pretty slow. Enthusiastically I jumped into the RDX, twisted the key and the car started right up and settled down to a normal idle. No stumbling or missing, no check engine lights. It felt like stock which is a good thing.

Driving around gently, I could feel boost building much earlier and throttle response was more responsive. Once up to operating temperature I headed for a favorite back road to start flogging the car more. A few things were apparent: there’s a massive increase in low end torque; the tachometer pulls hard from as soon as boost builds. Midrange is slightly stronger than stock, which was great to begin with, but the top end is my favorite part of this reflash. The stock RDX runs out of power above 5500 RPM, but with the Hondata reflash power builds strong right to redline. On the highway I found the new found power especially impressive in passing situations. The driver can choose to boost or rev and either way the job is done nicely. Passing cars around 4,000 RPM under boost is especially entertaining, as the RDX just scoots past them very quickly without fuss. In the back of their minds I could imagine them saying “what the hell was that?!” Call me crazy but I also noticed on the highway an increase in mileage which is always welcome.

With the reflash Hondata has been able to transform the RDX into a much more capable machine. The reflash is also very conservative. After talking with Hondata, it became readily apparent that these guys aren’t a bunch of yahoos cranking boost and fuel trying to make huge horsepower; everything has to be done properly, like it should have been from the factory.

 Before the flash I was averaged as per the RDX computer around 17.4 mpg (13.5 L/100Km). After the flash I am now seeing around 19.4 mpg (12.1 L/100Km). And I always boost and rev several times a day =) The RDX also seems to use much less gas when driving hard now. It really likes 94 octane fuel!

For anybody interested in giving their RDX the edge it lacks from the factory, the Hondata RDX reflash is probably what you’re looking for. It’s that good.



Copyright 2015 Hondata, Inc. All rights reserved. Warranty Information
Products not legal for sale or use in California on any pollution controlled motor vehicles.