Hondata Reflash - TSX 2006 TSX MT/AT K24A2

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Reflash your 2006 TSX engine computer.

  • Fuel, ignition timing and cam timing optimized.
  • VTEC point decreased from 6000 rpm to 4850 rpm.
  • Rev limit raised to 7600 rpm (AT: sport shift mode only)
  • Maximum torque gain 28 ft/lbs torque at 6000 rpm (AT: 24 ft/lbs)
  • Maximum power gain 32 hp at 6000 rpm (AT: 28 hp)
  • Peak torque increases from 165ft/lbs at 4700 rpm to 168 ft pounds at 4700 rpm
  • Peak power increases from 201 hp at 7100 rpm to 204 at 6800 rpm (up to 8hp - auto)
  • Very wide flat smooth torque curve. 90% of peak torque available from 2000-7000 rpm.
  • Fully dealer compatible - works with all Honda scan tools and equipment
  • California emissions legal (CARB EO D-742)

This is for an ECU reflash - the ECU is not included.  Hondata does not sell direct - the reflash must be purchased from a Hondata dealer. The ECU reflash form must be sent with your ECU.

This reflash will work very well with an 06 TSX in stock form, or with headers and intake.

How do I remove my ECU and immobilizer?

The ECU is located behind plastic panels to the right of the driver's right foot and the left of the passenger's left foot. Both panels will need to be removed. You will need a Philips screwdriver and 10mm socket. Complete removal instructions are to be found on this page. Alternatively you may download and print out the TSX ECU removal pdffile (300k).

Sales Region US
EPA/CARB status (USA) CARB EO D-742
Model TSX
Year 2006
Market US
Engine K24
Transmission MT/AT
Part Number 37820-RBB-A04 & 37820-RBB-A05 (2006 TSX MT)
37820-RBB-A59 & 37820-RBB-A61(2006 TSX AT)


Results for Manual Transmission 06 TSX with no modifications

  • Pink Line - Stock ECU
  • Blue Line - Reflashed ECU

Disclaimer. This smoothes and flattens the torque curve. You will lose the kick you had at 6000 rpm. As such it may be difficult for some people to "feel"the reflash. A before and after dyno will show the results though.

Click to enlarge picture

Driving Impressions

This reflash is difficult to feel because it keeps the torque delivery flat and smooth to a much higher RPM. Rather than the torque dropping 28 ft/pounds from 5000 rpm to 6000 rpm stock, the reflash keeps the torque drop to only 10ft pounds between 5000 and 7000 rpm. VTEC transition at 4850 rpm is also very smooth and hard to detect with a stock air box.

Results for Manual Transmission TSX with intake

  • Green Line - Stock 06 with reflash
  • Red Line - Stock 06 with reflash and cold air intake

Note the loss in torque from 2400 to 3200 rpm. Intakes such as the Comptech Icebox will not do this.

Click to enlarge picture

Who can use this upgrade?

Any 06 TSX K24A2 TSX with the ECU part numbers (covers all current 06 ECU part numbers) :

  • RBB-A04 & A05 - 06 TSX
  • RBB-A59 & A61- 06 TSX Auto
  • Solid green line - Stock ECU
  • Dotted green line - Reflashed ECU

Click to enlarge picture

Driving Impressions

This reflash is difficult to feel because it keeps the torque delivery flat and smooth to a much higher RPM. Rather than the torque dropping 28 ft/pounds from 5000 rpm to 6000 rpm stock, the reflash keeps the torque drop to only 10ft pounds between 5000 and 7000 rpm. VTEC transition at 4850 rpm is also very smooth and hard to detect with a stock air box.

Tuning Notes

These graphs show the best of the stock Auto ECU vs the worst of the reflashed. The red line between 6500 rpm and 6900 rpm shows the correct power and torque curves. The green spike in these locations is due to the torque converter unlocking before gearshift.

The reflash shows a few ft-lbs of torque more than expected. This may be due to the fuel tank being topped up with a different variety of fuel between the tests.

VTEC and Rev limit are identical to the manual with a maximum gain of 25 ft-lbs and 28 HP at 5800 rpm. The 7600 rpm limit is only available in sportshift mode.

Overall the reflashed 06 Auto performs very well easily beating a stock (non reflashed) 04/05 manual above 5000 rpm for power and torque.

The 06 TSX has the following improvements:

Increased intake flow:

  • Intake valve + 1 mm oversize
  • Intake cam High lift lobe with 0.9 mm more lift and 12 degrees more duration
  • Throttle body increased from 60-64mm
  • Radius on some intake pipes increased from 70-80mm

Increased exhaust flow

  • Exhaust Head pipe increased from 60-65mm
  • Higher flow catalytic converter
  • Main (single) exhaust pipe increased from 54-57mm
  • Rear (twin) pipes increased in diameter from 42.5 to 45mm

Block improvements:

  • Additional air passages in crankcase for reduced pumping losses


  • Stronger connecting rods
  • New crankshaft with more counterbalance weight
  • Revised pistons with more valve-piston clearance

04 TSX and 06 TSX comparison

This compares a stock 06 MT TSX with a stock 04 MT TSX. Both cars had lessthan 1000 miles at the time of the dyno. As you can see differences are mainlyat the top end on the high cam. On the high cam, the 06 generates about 15HPmore

Lets compare an 06 MT TSX with reflash to an 04 TSX with reflash, intake andheader.

- Blue line 06 TSX with reflash

- Yellow line 04 TSX with reflash, intake and header

As you can see the 06 just with the reflash is equivalent to 04 + header +intake. Thus an intake and header on the 06 will put it much further ahead ofthe 04 TSX. See abovefor an 06 MT TSX with intake.

The TSX uses adaptive knock control. This means it will listen to the knock sensor and advance or retard the timing appropriately. This is good as it means the TSX will readily adapt to higher octane fuel and add a couple of degrees ignition advance. The TSX ECU only takes 3 or 4 power runs to adapt, and is constantly relearning. Unfortunately the side effect is that successive power runs can vary by up to 4-5 ft pounds of torque due to engine noise or knocking that is inaudible to the ear. If your coolant temperatures are too hot (>195F) or the engine is hot from dyno runs, the ECU has a tendency to retard the timing.

All NA K24 engines we have tuned drop sharply in torque after 6000 rpm -even the 270hp full race engines. This is a function of the long stroke of the K24engine. The best way to change the shape of the torque curve is to improve the cylinder filling above 6000 rpm with forced induction - such as supercharging in this comparison with a supercharged K20A3 Civic

The intakes on the K series engines get very hot. They have a metal intake gasket which transfers heat from the head very quickly and are heated by hot air from sitting right behind right the radiator . Pay lots of attention to keeping everything cool and you will see results. The K24Hondata intake gasket reduces intake temps about 15-40 degrees F. Use a cold air intake where possible.

These instructions document the removal of the TSX ECU, and immobiliser for reflashing by Hondata. The TSX ECU is located between the driver's and passenger's footwell.

Tools needed: Screwdriver, ratchet and 10mm socket.


By the drivers right foot there is a triangular plastic panel. Hold the outer plastic ring with one hand and turn the center plastic Philips screw 1/8th of a turn counterclockwise with the other. The plastic Philips screw should then be easily pulled straight out.


From the top section of the triangular panel, remove the metal Philips screw.


The panel is secured by three spring clip fittings located as shown here.


Pull the plastic panel out.


Pull back the carpet and undo the left 10mm bolt holding in the ECU.


Repeat for the right hand triangular kick panel.


It is secured by only one plastic Philips screw.


The three spring clip fittings are located here as shown.


Unclip the 4 ECU connectors. The clip to depress is located on the top middle of each of the 4 ECU connectors.


Unbolt the second of the two 10mm bolts securing the ECU.


Slide the ECU out. It is quite a tight fit.


Insert the ignition key and turn the steering wheel to the left by about 45 degrees. Depress the top plastic in at the centre by about 3mm. This is to clear a clip located on the bottom piece of plastic. There are three clips on the left hand side. And three on the right.


Rotate the steering wheel to the right and repeat.


The location and structure of the three right hand clips from outside.


And from inside.

Remove the three screws holding the bottom piece of steering column cover on.


Lower the bottom steering wheel adjustment arm. You will need to move the steering column in and out as well as up and down to remove the lower piece of plastic.


The immobilizer transceiver is the circular plastic ring closest to the head of the ignition key. It is held on by two screws.

Make sure you have an unworn correctly sized Philips screwdriver as you do not want to burr the heads on these screws.

The three items needed to be sent are one key, the immobilizer and the ECU.


Transfer these serial numbers onto the reflash form and send to your dealer.