Hi,

I own a 2010 Mazda 3 with 109K miles. The engine has given me no problems until recently. I am trying to understand why I am not seeing any error codes when my check engine light is on.

For the past month, the check engine light has been coming on. It will turn off for awhile and then come back on when I am driving. My $20 Amazon OBD2 scanner is not reading any error codes even when the check engine light is on. The Autozone reader did not see any error codes, but but said there was a communication problem. Today my check engine light turned on and then the AT light went off and on also.

A few weeks ago I took it to a local shop and they claimed I needed a new transmission and told me it would cost $9000. . Ridiculous. I drove it back home and decided to buy my own scanner and see if I can repair myself. I don't think I need a new transmission.

Why am I not seeing any error codes from the OBD2 scanner if the check engine light is on?

Thanks for any help.

Best

Curtis

 

Some scan tools are sophisticated enough to read all the fault codes.

 

Thanks, makes sense and I suspect the scanner was of poor quality. The light turned off again and hasn't come back on yet. Next time I will try the scanner at Pepboys to see if that works or buy one of better quality.

 

Does the transmission work properly with and without CEL light on?

 

Seems to work okay - been I have been driving on back streets only. My wife said she felt the car lurch on the highway one time and check engine light came on, but I have not noticed it.

 

have you installed one of those gas saving devices i did on my mazda and put in a flex fuel found out flex fuel doesnt work in Mazdas except for one brand of truck so thank God i was under warranty and they replaced my sensor at no charge to me.
Lynnette