I have recently had an issue with my 2008 Mazda 6. The AT warning light will come on when driving and when this happens the transaxle will not shift past 3rd gear. I can unhook the battery on the car a few minutes and this will clear the warning light and the transaxle will shift fine again. I'm thinking possibly a sensor issue?? Any ideas???

 

Was curious as to what you may have found with the trans. The only down side of the battery disconnect is clearing any codes that may have set.

When a fault is detected in the trans, it automatically operates on "Limp In' mode. The trans raises the line pressure and shifts itself into 3rd gear. It allows you to get off the road or down the road but is rough on the trans itself.

Normally what I run into more than not is a connection problem. Usually a poor connection at the Trans Control Module. You'll need to retrieve the code from the TCM to find which circuit is at fault. Unfortunately, battery disconnect looses the codes.