2009 Mazda3, check engine and traction control lights on

Hey, guys! I haven’t been around much in the last couple years, but it’s good to see lots of familiar names still here!

I’ve got a 2009 Mazda3 hatchback, 31,000 miles. As I’m sure you know, it’s very cold in the Northeast today. It was -12F on my drive in to work! I went out to lunch with a coworker today, and it had warmed up quite a bit to about 25F.

As I was driving back to work - 40mph on a dry, straight stretch of road - my check engine light and traction control/stability control light came on. They aren’t flashing, just steady. The traction control light will flash if I hit a particularly bad patch of slush, but it’s never lit up on a dry road before.

Right after the light came on, the automatic transmission started feeling…funny. It was shifting hard, although downshifting felt okay. My coworker even noticed before I said anything. I don’t think it was the traction control - it was specifically as the automatic transmission was shifting, not at any other time.

I’ve read through the TSBs and didn’t see anything relevant, and I’ve already made an appointment for tomorrow at the dealer. I’ve only got 5,000 miles left in my warranty so I’m a little nervous - the car has been terrific so far. Anyone have any thoughts? I would think the traction control light would be unrelated to the transmission, so I’m a little confused.

Also, just to rule out a few other things - the last time I got gas was about a week ago and I still have a third of a tank. I don’t think this is a gas cap problem or frozen gas, both of which I’ve experienced before (in other cars).

Any ideas? Thanks!


Followup: I just told my boyfriend what happened and he says he had something similar happen with his old VW Jetta, and it was the traction control causing the “hard shifting” feeling. So I may be wrong about that aspect of it!

We’re going to pull the codes tonight before I drop it off at the dealership, so I’ll post back if anything pops up.

You need to get the OBD II codes read to make any intelligent guesses about it. From the symptoms, it sounds like it might be a vehicle speed signal/sensor problem.

The traction control/stability control light is on as a result of the Check Engine Light being on.

After the trouble codes stored by the OBD system are read, and after the problems related to those codes are resolved, both lights will turn themselves off.

That CEL (check engine light) is just a kid in class waving her hand trying to get you attention because she has the answer. You need to have the codes read. Some places will read them for FREE. Try Autozone or Advanced Auto Parts. Get the exact code (like P0123) not just their translation into English and post it back here.

Like I posted earlier, I’m going to read them after work. I don’t happen to have a code reader on me. I was just hoping for some insight before then.

Thanks, VDC. I didn’t realize that the TC light might be on just because the CE light is on for another reason - and of course the manual doesn’t say anything about that. That makes sense though. I guess I’m back to having no idea why the CE light is on until I can scan the codes tonight.

I found one code, P2128: Accelerator pedal position (APP) sensor No.2 circuit high input. Definitely not something I would have guessed - VDC was right about why the traction control light came on as well. It’s at the dealer now.

That was fast…they found the code but the CEL is now out and they couldn’t find a problem with the APP sensor so they aren’t doing anything. It should be covered under the warranty if I have a similar problem in the future though.

They’re recommending a transmission flush. At 31k, I know I want to change the fluid and filter sometime soon anyway. I’m waiting for a call back with prices on flushing versus cleaning the pan and replacing the fluid and filter. Anyone have any experience with Mazda’s flushes? I’ve read on mazda3forums.com that some dealerships use lower-powered flushes and that regular flushes shouldn’t do any harm to the transmission, but I know lots of guys here recommend just cleaning the pan and replacing the fluid and filter. I tried calling my independent mechanic for quotes too, but the owner ran out for parts and his helper can’t give me prices.

I think that’s pretty stupid of them. The redundant pedal position sensors are there to prevent safety problems like unintended acceleration. If there was a stored code about trouble with it, I’d replace it in a heartbeat. Imagine if the car were to go out of control and the jury at the eventual lawsuit were presented with the evidence that you now have that the dealership knew there was an issue but did nothing about it.

I’m a little underwhelmed by this visit myself. I just heard back from them that their version of a transmission flush doesn’t involve dropping the pan, so I won’t be having the work done there.