[Jimbo247]

I recently purchased a 2012 Mazda 3 touring I coupe from a relative that was a relatively trouble free one owner car with 116,500 miles on it. The car sat for about a year and had the automatic shift cable and oil pan replaced. Shortly after I purchased it the check engine and service traction control lights came on upon cold starts. This was accompanied by a rough idle and hesitation. When I shut the car off and restart it only the check engine light stays on and the car appears to run and operate normally. I took the car to my local Mazda dealer, and they replaced the program control module and reprogrammed. When I picked the car up, none of the warning lights were on and the car operated normally. After sitting for a few days when I cold started the car the original issue returned with both warning, lights being on. I took the car back to the Mazda dealer and after having it there for about 3 weeks, they told me that they discovered that the program downloaded to the new PCM was corrupt and they reprogrammed it. I picked it up and the warning lights were off and the car operating normally. After sitting for a couple of days I got in the car to cold start it and the same issue returned. The dealer seems to be at a loss. Any help in identifying what could be causing this would be greatly appreciated.

 

[Tekboy]

My experience last week was similar. I would strongly suggest that you pay particular attention to the batter and the cables/terminals.

 

[Grendel65]

Many of us and specifically Audiophile and trackers have found that the OEM power cables from the battery to the starter and grounds are too small (load capacity demand)? That is both an opinion and also doing the math of basic electrical loads can be arguably correct!
The import thing is to have the very best connectivity on the power terminals from the battery to the starter and also the battery to ground.