I think I just ran into this: I got the transmission light on the dashboard (cogwheel with exclamation sign in its center) the other night and a service engine soon light too. I read the codes off the ECU and got only one code: "Air Mass Sensor".

So, I overlooked that code because I did not think an "air" sensor could affect the transmission, so I thought for sure the transmission was messed up. The car was now shifting very rough, especially when it would downshift as I approached a traffic light or any kind of stop...

So, I took it to a shop that specializes on transmissions, and left it with them for the day. They called me later to tell me that the transmission looks fine and that they are 99.999% sure it is the "Air Mass Sensor" code that is causing the computer to make the transmission shift roughly, because when they cleared the "Air Mass Sensor" fault, the car shifted just fine.

So... I am gonna go clean the MAF sensor as recommended here and see what happens...

The transmission shop was also able to read other codes which my ECU reader did not show, they are:

- (8) Air Mass Sensor Signal
- (149) Can Wheel Speed Signal
- (146) Can Engine Intervention Interface
- (33) Wheel Speed Sensor Front Left Circuit