Hondata FlashPro is the most popular engine management solution for both the American Acura TSX and the European Honda Accord. For this generation, it's only available for the CL9 platform utilising the K24A2/K24A3 engines. Other complete management solutions include Hondata K-Pro or the up and coming K-Tuner, both currently at the cost of losing cruise control completely. Worth noting, for Accord's running the standard 4.3 ratio final drive, cruise control will not work without swapping up to the TSX/EP3/DC5 4.7. I'll cover this in more detail on my car's project thread.
- Difficulty Level:
This guide is an amalgamation of my experience from several different days of working on the car, coupled with bits of advice from random threads across the net and other people before me who have completed this conversion. I intend it to be an all-encompassing guide, and I'll try my best to provide all the information needed to get up and running.
Applicable Vehicles (CL9)
Honda Accord (2002-2006) Pre-Facelift K24A3
Honda Accord (2006-2008) Facelift K24A3 [Vehicle Used]
Acura TSX (2004-2006) Pre-Facelift K24A2
Acura TSX (2007-2008) Facelift K24A2 [Only Section 4]
Although this guide is based on our European Accord, specifically my Facelift, it should also work on all EDM/AUDM/JDM 02-08 CL9 Accords, and the process is also similar for 04-06 TSX owners - the major difference being the location of the CANBUS wiring. For 07-08 TSX owners, you can jump right into FlashPro without the need for the first 3 sections.
Pre-Requisites for Installation
Hondata FlashPro (FP-TSX-US)
Hondata FlashPro Harness for the 04-06 TSX [Required for all 02-08 Accord, though custom wiring explained below]
'07-08 Acura TSX ECU (M/T 37820-RBB-A21 or A/T 37820-RBB-A71) [M/T can run on an A/T ECU without issue]
Windows Laptop/Tablet [Mac/Linux VM works fine]
Internet Connection [Software Downloads]
Small Electronics/Jewellers Flathead Screwdriver [Supplied with FlashPro Harness]
Trim Removal Tools [Optional but recommended]
In this guide I will also cover programming the new ECU to the car, as well as pairing the existing immobiliser which is needed in order to start the car after any ECU replacement. If you don't have the needed tools below, this can be done at any Honda dealer, you'll likely just incur an hours labour cost.
Extra Pre-Requisites for Immobiliser Reprogramming
Honda Interface Module (HIM)
Honda Diagnostic Software (HDS)
EPM-Code from Honda's MaRIS Network
1. Harness Installation - Pre-Preparing for the ECU
On the '07-08 TSX, the DLC (ODB2) port is connected to the car's CAN system, this differs from all other CL9 models, and allows FlashPro to utilise the CAN protocol in order to make speedy rewrites to the ECU. On other models, the CAN system is only used for dashboard communication and doesn't extend to the DLC connector. This section covers converting the DLC connector to tap into the existing CAN system - without it, FlashPro cannot communicate with and write to the new ECU that we'll be installing later.
For RHD Accords, you'll be removing the fascia under the steering wheel pictured below. For LHD Accords or the TSX, you'll be removing the glovebox (fairly straight forward, push in the tabs on the left and right hand side to allow it to drop down and gain access).
To remove the fascia, there's a single crosshead screw to be removed on the bottom right hand corner under the coin pocket.
Then use a trim removal tool to lightly pry away the fascia from the right hand side, and work your way around until it's free from all the tabs:
With the fascia unsecured, finally disconnect the two plugs for the headlight adjusters and VSA controls:
Next up we'll be removing the DLC connector from it's holder in order to better access the plug's wiring to make some changes. Push the tabs in both sides of the connector and then push up to free it from the metal holder:
The next part we'll need to be able to access is the CANBUS wiring. For the RHD Accord, you're looking for the grey set of plugs hidden away behind the white and then green plug sets pictured below. On the Facelift Accord you'll have white/red positive/negative wires coming from it.
On the Pre-Facelift the layout looks slightly different, and you'll also have some brown earth wires, this doesn't change the installation in anyway. Original image credit to Kane:
You'll be looking for the green connector below, in the following instructions you'll be using the top most spare plug:
Your plugs should look the same as for the RHD, however the placement will vary slightly. If you're following this guide, please upload a picture to use here for other LHD owners.
For easier access if you wish, the set of blocks pictured above is held in place by a slide-in latch at the back, carefully work/jiggle the block set towards you in order to free it. Leaving it in place and just reaching back to plug in our connector will also work fine for those nimble fingered:
You can then again slide off the CAN connector block from the others:
Now we've identified the DLC and CAN plugs to work on, it's time to get busy with the wiring. We'll start with the CAN side of things. If you're using the proper Hondata harness, this process is going to be a lot less complicated for you. If you do not have a Hondata harness I would strongly recommend sourcing two ODB2 wires with the proper pins to make your connection as below, otherwise bridging the relevant connections with any old wire would be a bit of a botch job, and you're going to struggle to get a solid connection (believe me I tried with two wires/pins from a car stereo connector before deciding to get the proper harness).
Referring again to the CAN plugs above, the red and white wires are all connected in "series". This means that all the wires are common and tapping any of them for a connection would be fine if you haven't got a harness, they're all interconnected. For the harness route, identify which way around the plug will sit into the empty slots on the block and appropriately attach the wires from the harness cable (on the end marked "Green Dash Connector"). You'll notice on the wire's pins that there's two prongs and forming a U shape which identify which way around they will sit in the plug:
Next add your newly wired plug into one of the spare slots on the CAN connector block:
If you've removed the block from its holder, you can now go ahead and replace it:
Let's not be messy, use some cable ties to coil that big long cable up and keep it out of the way, for the RHD application you won't need much length to reach your DLC connector:
If you haven't used the harness, you should now be at the point of having tapped two wires into one of the existing red/white wire pairs.
Next-up, it's time to rewire the DLC connector. This involves repositioning one of the existing wires, and then adding our two new connections from the CAN system. Let's first look at the plug layout, bare in mind this is from the front (connecting face):
The pin layouts are as follows:
Stock '02-08 Accord or '04-06 TSX
- BLK Ground for FlashPro
- BLK Signal ground for communication
- BLU K Line Diagnostics
- BRN Service Check Input
- RED/WHT (06 TSX WHT) WEN
- GRY Immobiliser Programming [To Be Moved]
- WHT/GRN +12V Power for FlashPro
Finished or '07-08 TSX
- GRY Immobiliser Programming [Final Position]
- BLK Ground for FlashPro
- BLK Signal ground for communication
- WHT CAN Program High [New Wire, White]
- BLU K Line Diagnostics
- BRN Service Check Input
- RED/WHT WEN
- RED CAN Program Low [New Wire, Red]
- WHT/GRN +12V Power for FlashPro
This part I've been told by many is the biggest annoyance of the whole modification, personally I didn't have much issue but then again, I'm used to fiddling with computer hardware regularly. I'll try explain this as best I can.
On either side of the DLC connector, there's two little covers which keep the wires and pins locked in place. Using an electronics or jewellers flat head screwdriver, gently pry them away from the block. The image below is from Hondata, I personally started at the edge and worked my way along:
The finished article should look something like this:
Next, the more fiddly part. We'll first be swapping the grey wire for immobiliser reprogramming from Position 14 to Position 1. We need to carefully pry the pin from it's latch, the illustration below should help you see how this works:
As you push on the latch you want to gently pull on the grey wire to free it from it's position. Again, be gentle, I managed to push through part of the plastic on my particular connector. It will come free, just start about half way down:
Once the wire is free, we want to reposition it to Position 1. Pay attention to which way around the pin fits into the socket and it should securely latch itself once pushed in. I found on mine, I had to come back and redo this as when I later attached a plug, the wires pushed out. Make sure it clicks.
We can now work on attaching our new CAN wiring into the DLC connector. Referencing the pin layout above, place the White wire into Position 6, and the Red wire into Position 14. If you're not using the Hondata harness and instead spare ODB2 pins/wires, the process will be the same. If you're freestyling this completely and soldering or the like, wiring up the connector securely may prove to be a pain without the connect pins holding them into place.
Once done, you can then push down the grey locking flaps on either side of the connector and be left with something similar to this:
The DLC and CAN wiring should now be complete, you can replace the DLC connector back into its holder:
We don't yet know if our rewiring was successful, so I would suggest leaving the fascia off for the time being until you've either completed the 3rd step, or visited a Honda dealer and successfully reprogrammed the Immobiliser/ECU.
2. First ECU Installation
Well, that's the harder fiddly part over and done with. We're now onto getting in our new ECU. As mentioned at the top of the guide, for this part you can use either a Acura TSX '07-08 Manual or Automatic Transmission ECU, regardless of which you have in your vehicle (part numbers at the top, you can check compatibility here). FlashPro can overwrite either ECU with the correct transmission for your vehicle, be aware that with the A/T ECU on a M/T CL9 the only side effect is that reverse lockout (stopping you selecting reverse while cruising) will not function.
We haven't got a running vehicle yet or checked our previous wiring, so unless the car doesn't need to be driven, we'd be silly permanently installing the new ECU at this point, I'll cover that at the end. For now, we'll be gaining access to the existing ECU and using it's connector blocks while it's still attached to the vehicle.
For RHD Accords we'll be working in the passenger footwell, for LHD Accords or the TSX, this will be on the drivers side. We'll be removing the small panel to the side of the centre console, conveniently left by Honda for easy access:
Securing the panel in place is a single plastic push screw, using a crosshead screwdriver remove it and the panel itself:
Next, we have a bit of air duct piping in our way, so let's carefully pry that free by pulling on the top. The plastic can easily be manipulated so gently working at the points it connects should easily free it from it's position:
We now have decent access to the ECU.
Going into the ECU are 4 uniquely sized connectors, pushing down on the tab at the top, gently pull them from the ECU and use the connectors to wire up our new '07-08 Acura TSX ECU in-situ:
The new ECU is now temporarily connected up so we can get it reprogrammed to the car, and a suitable base map flashed onto it. At this point, check that your ignition lights come on correctly, a MIL or CEL is completely expected. Note, that until your Immobiliser is reprogrammed, the car will not start:
3. Pairing Your Immobiliser & Rewriting Your VIN
It's now time to get our new ECU working correctly with the car. This step is optional in the sense that you can take your car to any Honda or Acura dealer to get your ECU successfully programmed, we're going to go the DIY route here and do it ourselves - that's the fun of modifying, right?
As mentioned in the pre-requisites, in order to get this step completed yourself you will need both a Honda Interface Module as well as the Honda Diagnostic Software up and running on a Windows laptop or tablet (or Mac with Bootcamp). I won't properly cover here getting started with the equipment, however for reference I am using a cloned HIM with the HDS software supplied, this post covers where I brought it from. You'll also need a Serial (RS-232) to USB adapter for most modern computers as they don't often come with one, the adapter also has quite specific driver requirements and needs to be allocated the port COM1. Start a new thread if you have any questions about getting up and running with HIM/HDS.
Check that your computer running the HDS software has sufficient charge or is plugged into the mains, the HIM is also ordinarily powered from the DLC/ODB2 connector itself so I'd recommend not proceeding if your car's battery has a low voltage, your ignition will be on for quite some time.
Let's get started, boot your HDS machine and connect the HIM upto it. Turn your ignition on, wait for the dash lights to settle, and plug up the DLC/ODB2 connector:
If your HIM is successfully interfaced with the car, you should see the green (power) and orange (communication) lights flashing one after the other showing that it's waiting for the next command. If you don't, or have the red light is showing, chances are you need to revisit Step 1 - I'd recommend the first area to look in troubleshooting is the DLC connector itself, as I mentioned before the first time round I didn't secure the pins properly in the DLC connector block and connecting up the DLC pushed the wires slightly out.
Anyway let's assume all is well, it's time to open up the HDS software:
On the right hand toolbar from the image above, select the top icon to interface with your vehicle, the screen below will appear:
If you haven't interfaced successfully, you will be greeted with the prompt below. Either the ignition isn't on, you haven't connected up the HIM correctly, there's a driver issue, or your earlier wiring in Step 1 wasn't successful. Once you've ruled out the basics, double check the steps so far before hopefully proceeding:
If all is well, you'll now be brought to the car details page:
You'll see above that the HIM is reading the new ECU's original TSX VIN number as I'm using one sourced from a breaker in the states. Prop the bonnet and take a look at your vehicle identification plaque on the top of the offside strut tower.
Using your VIN number and your current odometer reading from the dash, fill out the information requested.
You'll then be prompted to write your car's VIN number to the new ECU:
A brief wait, and...
That's the first part done, the ECU is now coded to your vehicle. Next up, recoding the immobiliser.
After a short wait while the HDS processes data from the CEU you'll be brought to the main screen, select "Honda Systems" from the options:
Next-up we want the self-explanatory "Immobi" section:
After a prompt to keep the ignition on until told otherwise, go into "Immobiliser Setup":
Next we want to go through the "ECM/PCM" (ECU) replacement procedure:
Now we need the final pre-requisite explained at the start of the guide. You'll need to obtain a PCM-Code from Honda's MaRIS network in order to modify the immobiliser system, this can only be obtained with dealer level access. This is based on the car's VIN and codes generated only last a set period before they eventually expire. If you're reading this and are not currently a registered club member, I'd suggest speaking to your local dealer, otherwise you can drop one of the club admins a message, or ring our club dealer Holdcroft Honda for further assistance.
After the prompt screen, it's time to enter our code, complete with a virtual keypad:
After entering your code, you'll have short wait period while the changes are processed. Follow the on-screen prompts turning your ignition on and off when specified. All being well you'll hopefully be relieved to see the following notice:
Next up, we'll be quickly testing all of our keys to ensure they correctly allow the car to start and the transponders are functioning correctly with the immobiliser. Bare in mind when you first turn your engine she'll be idling high as your ECU has been reset. Accord owners will also at this point have a CEL which relates to sensor differences between the TSX and Accord. We'll get that sorted in the next section as we get the car remapped.
We're all done, turn the ignition on one more time to finalise the process and follow the on-screen prompts.
There we have it, your new '07-08 TSX ECU is now programmed to your car. Exit the HDS software and disconnect your HIM, we'll be using FlashPro from here on out. Let's get a base map in so we can finally go burn some rubber.
4. Flashing a Base Map & Removing CEL
We have a functional car, though she's currently running the stock map from the '07-08 TSX which has numerous subtle differences, mainly relating to larger bores on exhaust and intake piping, as well as more aggressive intake cam profiles. Let's get about putting on a new base map written by Hondata that's more suited to our set-up - and can serve as the base for you or your tuner to tweak and manipulate to best suit your car and its mods at a later point for the maximum gains.
For this section, we'll simply need a laptop or tablet running Windows in some form (through a VM is fine) with a copy of FlashPro Manager installed. When installing you'll be prompted which base maps you want to download for use in the manager, you'll just need the M/T or A/T maps for the Acura TSX depending on which your vehicle is.
As with working with the HDS in the last section, we'll be starting by booting your machine, turning the ignition on in the car, and then connecting the FlashPro unit to both the ODB2/DLC connector, and your computer's USB port.
Start FlashPro Manager, you may be prompted to install the USB drivers if they weren't successfully installed earlier - go ahead and do this if that's the case. All being well, you should have green "Driver", "FlashPro", "ODBII" and "ECU" status indicators at the bottom left hand corner. The first series of screenshots here are from before I finished the initial wiring so the "ECU" indicator on mine is still red.
Our first port of call is to register and activate our FlashPro device, select the "Window" option from the top toolbar and select to show "FlashPro":
Select the "Registered Owner" tab across the top, and fill out your details as below. Once complete select the "Update FlashPro with Owner's Details" option, followed by "Register FlashPro with Hondata".
Next-up confirm your ECU is being correctly read by FlashPro by selecting the "FlashPro" tab on the same window, and confirming the "Binary" is showing starting with "TSX US". If it isn't, double check your DLC wiring that was completed in the first step.
All being well, select "Online" from the top menu followed by "Lock to Vehicle".
Your FlashPro device can only be used on one vehicle at a time, if you wish to use your device in the future on a different vehicle, you will need to select the option below the previous option, "Return ECU to Stock" in order to then later lock the unit to a different vehicle as explained on the screenshot below:
The locking process will take 60-90 seconds:
If all is well you'll be greeted with a success confirmation:
We're ready to go, FlashPro is now successfully paired and locked to our car, it's time to get into the map itself. From the top menu select "File", followed by "New Calibration":
On the next screen we'll be given all of the Hondata tuned base map options currently available for the CL9. The first point to note is that the option highlighted "04-05 TSX basemap" is your best option for all close to stock Accords, even the Facelift, as we didn't see the same post-2006 performance improvements that the TSX did. If you've already got I/H/E installed check options 3-5 for the closest match to your current setup. The options thereafter are base calibrations based on different fuel injectors, our stock 310cc are good till for nearly 300hp before they are properly maxed out.
Whichever map you choose, bare in mind that although your car should be perfectly fine for daily driving, ideally you want this map tweaked as best as possible for your particular set-up, in particular there's numerous reports that the fuel mapping is slightly rich for the Accord, regardless a great improvement over stock.
Once selected, you're into the bowels of FlashPro Manager, feel free to poke around the various windows and options available to get familiar - though for the sake of this guide, we're going to keep it simple with just the basics to get you up and running.
For Accord applications, the only tweak we're going to make for now is disabling the "EVAP" sensor DTC which is currently causing our CEL. From "Options" in the top menu select "Show Advanced Parameters", then back on the "Calibration" window select "Misc" from the bottom, and untick the "EVAP VSV error check enabled" option.
Amendment: I've been informed that two Pre-Facelift Accord users had problems with throttle lag when taking off in first, although I haven't experienced it myself, to be on the safe side: again with "Show Advanced Parameters" on the "Calibration" window, click "Throttle" and ensure '1st Gear Throttle Dampening Enabled' is deselected.
That's a suitable base map prepared, from "Online" on the top menu select the "Upload" option to flash the new map to your ECU.
The upload process can again take a minute or two, be patient:
When it's complete, the confirmation message will be displayed:
That's that, your ECU is now up and running with whichever base map you selected, the "EVAP" related DTC is disabled, so no CEL should appear. Disconnect all your hardware, and go test drive. Bare in mind throughout this process you will have reset the ECU, it'll take a few minutes for the TPS learn process to complete and the idle revs to drop down to normal.
My first experience was noticing the fuel injectors were slightly louder than before, naturally the fuel map has been tweaked so this is expected - though it was accompanied by a subtle petrol smell. My immediate instinct was that the car was running slightly rich, and after speaking to others such as @AccordBrit, that appears to be the case for the TSX maps on the Accord.
Ideally we want a better base map for our models so that custom tuning isn't required by each person who follows this process with a close to stock car, and they have something they can drive around with having full peace of mind until they decide to go modifying further. In my case, I'll be getting datalogging complete using FlashPro and working to tweak the map. I may eventually amend a final part to the guide explaining this process.
If you want more information on what to expect after reflashing, read my initial thoughts here. I honestly couldn't be happier with the gains from the base map alone.
5. Permanent ECU Installation, Final Touch
It's time to properly install the '07-08 TSX ECU and get the car back to normal. This process is luckily very simple, and will take all of 10 minutes to finish.
First off, we'll be starting in the driver's side footwell. For the TSX or LHD Accord this will be the passengers side. Next to the dead pedal is a small plastic push screw to remove:
On this side, there's also a normal crosshead to remove just above it:
Remove the panel, and underneath we'll be greeted with another air duct to remove:
We now have the room to work, though in order to pull the carpet back a little further (mainly for photos), I then went ahead and removed the dead pedal with a trim removal tool:
Finally, remove the 10mm nut securing the ECU in place:
We can now get to work on the other side, for the sake of ease I'm going to assume you still have the TSX ECU temporary installed to the side of the center console. Go ahead and disconnect it by removing the 4 blocks:
Next, there's a small plastic clip securing the ECU wiring in place, push the tabs in and then forward to free it from it's position:
The bracket itself is still in our way of getting the ECU out, remove the single 10mm nut securing it in place at the bottom:
Finally, remove the remaining 10mm nut securing the ECU itself in place:
ET viola, you should now simply be able to pull the ECU forward and through to remove it:
Installing the new ECU is extremely straight-forward, you're simply following the process so far in reverse to put all the pieces back together.
The car's running, every is neat and tidy, go enjoy fruits of your labour. This has been the largest guide I've ever written, the picture quality and writing style has likely changed a few times throughout but I've done my best to catalogue the complete process for the ease of future 7th Generation Accord and 1st Generation TSX owners who want to follow this route.
The CL9 is one fantastic car in general, I'm on my second, but it's let down by the conservative map. I'm going to quote a previous comment which illustrates just how remapping benefits the K24, a nice way to finish off the guide:
Any questions, queries, comments, mistakes spotted, or whatever - just leave a comment and I'll improve upon the guide as necessary.