U0122 Code - AFR and other stuff is wack
 

So I was taking out the battery the other day and I accidentally caused some sparkage and it blew one of the fuses on the battery positive terminal side. No big deal.

Then I took the car to the dealership yesterday (it was driving just fine) and after an hour they determined that they needed to get the new fuse from Subaru, so it'll be in today. They gave me the car back with a check engine light. And I told the service guy too. (Prior to bringing it in to the dealership there were no CEL's. There haven't been in a long time.)

Drove over to Autozone and they pulled the U0122 code (U0122 FCAN Malfunction (ECU to VSA)). Have no idea what it means but my car is driving like crap now. Any time it goes over 3500-4000rpm the AFR levels go from safe to dangerously lean. I mean from about 11-13 to 16-17. Now I've obviously got a tune for the turbo and I'm not sure exactly what's going but it seems like the turbo is attempting to increase it's boost normally but the engine isn't getting anymore fuel to compensate the extra air/boost. I don't know/think the tunes were erased because I can still flip between the 2 tunes with the Ecutek feature on the cruise control lever.

I don't know what exactly to ask here but some pointers might be nice. Before or maybe after the Toyota dealer installs the fuse today I'm going to remind them that the CEL that they gave my car while it was in their shop yesterday, is still there, and I'm not the one that caused it. My car had no CEL's prior to bringing it in.

Any tips/ideas/pointers/etc?

Thanks!

I don't know why you brought a car to dealership. i wouldn't take a car to dealership especially with turbo on it. they have no idea what to touch and would mess it up.
they'll probably blame on your turbo to cause car like that.
Reset the ECU first then i would troubleshoot what U0122 code if it comes back then reflash the ECU regardless tunes weren't erased. (just in case)

Only problem with reflashing is that the cable/tune/tuner are all 1000 miles away in another state lol.

Sounds like you're screwed.

I would suggest reflashing, but another possibility is the ECU got f*ckd up with the current surge it received.


Also, you can get a loaner cable from someone local and get the tune via email to flash it in your car with your laptop.

Thanks, I didn't know that.

A bit of an update, I pulled the battery for 30 mins, hooked it back up properly, drove for 50+ miles and turned the car on/off several times, including meth on/off and flipping between the 2 tunes just to see if engagement would help.

It seems to be getting a lot better. I haven't seen an AFR go above 14.5 in 20 miles, and I also haven't seen it hit super rich at 10.0 in about 5 miles now. Seems to be operating within 10.5-13.5 most of the time. The gas pedal has also got back most of it's feeling, whereas before it would bog for a solid 1-2 secs and be terribly unresponsive at dead stops in 1st; or low RPM's in other gears.

Seems like all might be well.

I hope so. Good luck!

gas pedal you are feeling is that re-learning its position. no big deal.
since you resetted ECU by disconnecting the battery, hope everything comes back to normal.

It's broken. Deliver the car to me, I'll take care of it.

So Toyota fuses are different than Subaru fuses?

I would not go back to that Dealership.

Trust me, I'm not. There's a Lexus dealership that's near my house that I have a much closer relationship with that I'll be taking the car to instead next time. Their labor rate is also like $10-15 cheaper per hour.... and it's a Lexus dealership.