Hey all,
I’ve got a 2011 Mazda 6 with about 119k miles.
One day when I was driving back home from a road trip, my fuel cap light came on. Later that day I went to autozone to have the code checked out, but when I brought the tool into the store to have them look at it, the tool had picked up the wrong mileage (it said I had 70k as opposed to 119k) and said I needed a new ECU. This didn’t make sense to me, as the car has the factory ECU in it. I assume the tool is wonky and leave.
However, about 2 minutes after I left, a check engine light appeared. I took it to a different auto one (I still thought the first one had busted tools), and decided to scan the code. The tool at the second autozone said the same thing as the first one, including the incorrect mileage. I again assumed the tool was acting up, cleared the check engine light, and went about my day.
The car ran perfectly fine for about 300+ miles, until today when my airbag light came on, flashing code 42. Upon looking it up, I discovered that the code represents a communication error. I have no idea if these two events are related, but I am paranoid.
I have a few questions about this issue. Is this a serious electrical issue, or a bad ECU? Can I get the parts at a junkyard and try to fix it myself? Is it worth it to put on a “band-aid fix” and sell it? Any suggestions on what I should do?
Thanks in advance,
theQuarterPounder
Before you go replacing anything expensive, her are 2 things to check. Low voltage, due to any alternator and/or battery weakness will cause these kinds of intermittent warning lights and codes - the auto parts place will do that for you. Poor grounding of the ECU will also cause these kinds of problems - get some contact cleaner and clean all the connectors into your ECU.
Just got back from AutoZone, the employee said that the battery and charging system were both in good shape. Will check out the ECU situation as soon as I can.
I should note that the airbag light turned off when I shut the car off, but reappeared after about 40 minutes of driving
You have a rough one on your hands
Hos long have you had the car? Do you know the history of the car?
I have had the car for about 2 years. I am the second owner of the car, the first owner was my dad. The car hasn’t had any serious issues up to this point.
You need to scan all the live data related to the codes to find out what the exact issue is. Although the ECU issue can be a possibility which can be verified if the data are analyzed.