GuyIncognito

this evening I got into my 997 C2S ('06, ~30k miles), turned it on and the CEL came on.

earlier today I replaced the battery, cleared the PASM failure codes, and took the car for a long drive. put the car back in the garage. next time the car got started is when the CEL came on.

turned the car off, checked the gas cap, checked the fluids (dashboard dipstick and also coolant), no puddles under the car, etc.

turn car back on, CEL came on again. car sounds fine, drove fine, not in "limp home" mode, etc.

Is this something related to the battery swap earlier today?

full disclosure, car does have an APR ecu flash, no other engine mods (exhaust/intake/etc).

Thanks in advance!

roberga

No big deal if it is not flashing. Could be a number of things. Drive it a few days and see if it goes away. If you are worried just go to the dealer and have them clear the code.

GuyIncognito

update:

CEL did not clear itself. took it to the dealer this morning.

got a call about an hour ago, new ECU is on order from Porsche!

the car kept saying it has a bad O2 sensor, they replaced all of them and it kept coming up, so Porsche recommended replacing the ECU (under warranty, I am told; which is nice since my warranty expires at the end of the month!)

has anyone heard of this problem? was the new battery a coincidence or did that have something to do with the timing or cause of this problem?

Edgy01

Most likely a coincidence. It's quite easy to see something like that and assume it was related.

Bijan

It could be a coincidence but the ECU is susceptible to damage when connecting a battery, from surge spikes. Porsche recommendation is negative off first and on last to minimise this as much as possible.

LlBr

Good story. Problem solved. Warranty to the rescue. Thanks for the disconnect reminder Bijan.

GuyIncognito

If that were the scenario, wouldn't I have gotten the CEL upon the first start, not the second? That's the baffling thing to me.

LlBr

How about this? The thing was just waiting to go, the first didn't quite knock it over, the second surge did it. Just a guess.

alexb76

What if the APR program screwed some code up? Otherwise, there could be multiple of reasons for ECU to go bad...

roberga

**** happens and the warranty takes care of it. Did you get a nice loaner?

GuyIncognito

2010 Audi A4....might be the most boring car I've ever driven. my non-car-guy friends, who all drive Accords, are impressed, which says everything I need to know...

atr911

On a side note, how do you like the APR flash?

Fahrer

You also got new O2 sensors! That should be good for another 4 years or more.

GuyIncognito

I love it, seems completely seamless and noticeably more power. There might be a slight gas mileage penalty, but ~1 mpg (hard to tell if that was the flash or a driving condition anomaly thus far). I know a lot of people go with Softronic, so I'm not sure how they compare.

true, new O2 sensors too whole thing was covered under warranty which was a nice relief!

per the dealer, the new battery was the cause of the ECU failure; apparently it is fairly common. my advice: if your warranty is up soon, change your battery now!

Minok

Hm, if thats true, that is one awful ECU design.