I have a 2012 Mazda5 with 160k on it. I've had a CEL come on twice in the last week with both AT and TCS lights on and the "D" drive indicator light goes out for minute. After about 30 seconds everything goes back to normal except the CEL. The car seemed to drive fine when this happened. maybe shifted a bit hard. Computer had U0101 for engine and U0100 for AT. I'm thinking maybe bad ground or loose connector. Any thoughts on where this might be?

 

Hi, I know it's an old post but I'm hoping you found out what the issue was since my van started acting up exactly like yours also. Hopefully you can share the solution if you got it fixed.
Thanks

 

I disconnected the TCM and ECU connectors and cleaned them with CRC electrical contact cleaner. The problem has not reoccured in 10k miles since.

 

Thanks for the reply.
Is the TCM located next to the battery like the older gen Mazda5? Can't seem to find much info on our gen.

 

Not sure if you ever got this fixed but for those wondering. On 2012 at least the cm is located under the battery tray and driver side engine/trans mount or top of the transmission. You have to remove the air box assembly, battery and battery tray/ecm. Everything uses a 10mm socket and there's plenty of room. There are three bolts for the cm two of them can be a little tricky to access because of the engine mount. I'll try to include some pictures.


All parts that needed to be removed.


All electrical connections (Ecm and MAF) excluding the tcm connector.


Engine mount overview with tcm underneath.


Tcm overview from firewall pov.