Hi Everyone, quick rundown of my issue if anyone's got a suggestion, advice, or thoughts it'd be much appreciated...

2006 Mazda3 4 cylinder

My automatic won't switch into 5th gear, even when I'm in speeds that require it, it also has trouble starting in that it takes a little bit longer for the engine to turn over.

I know the turnover isn't the battery because it's new, and when I took it back to have it looked over they said it was in good shape but for some reason it wasn't operating at 100%--I know that may not have much to do with my dilemma but I figured I'd throw it out there.

Another interesting thing, about a month ago the dashboard lighting seemed to fade a bit in half of the CD player area, and the other half stayed the same. The problem went away after a few days, I just thought that it was odd and that was my reason for thinking it might be the ECU.

That being said, has anyone ever experienced this problem with it not switching, and if so what do you think it is? Thank you in advance!!

 

Sounds electrical alright.
Here's a suggestion, but it is a biggie: Disconnect the battery cables and touch them together for at least 30 secs. That should discharge any residual charge in the electronics out. Don't worry about sparking as the discharge will be very small. You will not electrocute yourself.
Then find all the electrical connections under the hood and the ECU. Unplug and plug them back in several times, but only one at a time. You might also consider getting some dielectric grease and stuffing some in each connection to help waterproof them in the future.
One more thing: Be sure to plug disconnect and connect these connectors as straight as possible to avoid bending the delicate and multiple pins that may be involved, especially on the ECU where there are many connector pins.
I am suspecting you have a corrosion issue on one or more of them. And if someone decided to use a pressure hose (water) under the hood, it's very possible that's what you're experiencing.
Another issue could be weak or corroded body grounds. It's been suggested by at least a few people that making sure the ground wires/connections on these cars is critical. You might even consider adding an additional one or more, just to be sure.

 

Awesome, thank you for that. I'll see what they have to say come Monday...I just didn't want to have to take it to the dealership if it was a transmission issue, for which I could easily find a less expensive shop.

I had a feeling it was the ECU but that's good to know when I talk to the service manager--Being a girl it's always nice to walk into an auto repair place knowing your stuff!


Anyone else want to second that or throw something else at me would be great.

Thank you so much, again!!