[everfeb]

pavich...just noticed this thread. Do you have atx or mtx? If you put PO128 into search engine (use capitals for PO) you'll find a few discussions on this CEL which only a few of us had back in '04, '05, '06. Happened mainly to '04 2.3 ATX owners. Had nothing to do with thermostat. I had my computer updated in feb '06 and both my gas mileage and heater improved. The problem was the coolant temperature sensor was reading the coolant as cold when it was actually warm. The update fixed it. Are you getting lousy mpg and poor performance from your heater?

 

[everfeb]

You likely didn't get many replies because only a few of us, who live in areas with very cold winters, had the issue. My update was done under warrantee. So I don't know what Mazda may or may not charge.

Are you the original owner. If not, check around the hinge of the driver side front door. If you see a sticker there your car probably had the update done before you bought.



Here are all the TSB's for the 3....
http://www.finishlineperformance.com/store/pages.php?pageid=12
Just scroll down to the one that mentions PO128 and click for information on this TSB.

If your check engine light hasn't come back on I don't know that I'd be rushing off to mazda to get the update done. Just monitor your mpg #'s.

I did say in previous post my mpg improved but it wasn't significant. What really improved was my heater performance. Prior to update it worked so poorly I was ready to trade it off as in -40* temps you do need a heater that works.

Good luck.