On Tuesday, my CEL came on and stayed on as I was driving down the interstate - 2225 miles on the odometer. My dealer got my 8 into the shop today - code was P0420 catalytic converter below specifications. The paperwork says they re-flashed the PCM but there is no indication of the version number (or letter). Does the re-flash mean an update? Or did they just reload the current version? I was in a hurry to get back to work, and the service writer was not sure. This was the first visit to the dealer)

 

It seems the RX8 is very sensitive to the catalytic converter below specifications meaning the temp got to low. Either the ECU flash up to the "m" flash will fix it or another sensor will have to be replaced. I have been bless with no lights and a great running 8 which is good since I have a July 2003 vintage. The M flash has smooth the engine out and gave me mileage from 16.6 to 18.2 in mixed driving.

 

RX8by -
how do you know what version is loaded? I don't really notice any performance difference (it is still great). The only thing that I can tell that is different is that they seemed to have moved my vehicle information sticker that used to be on the driver-side front door to the driver-side back door. ( It also seems that the tire pressure spec. sticker is different, as it now calls for 32 psi front and back where it used to be 33 psi). I guess I will wait until I take her in for the free dealer oil change and then make a point to talk to the rotary techician.

 

I had the same code back in February. When they re-flashed, the dealer installed a sticker on the bottom of the hood, near the latch specifying what upgrade was used for the re-flash.

I have had no further CEL codes since.