Weird codes on a 2001 S40

I've for a 2001 S40 with around 60K miles on it...

Been a great car.

Anyway, the battery was starting to have trouble starting the car on cold days. I got a new battery from Napa. After replacing the batter the following happened.

With 20 miles or so the Check Engine light came on. The car seemed very sluggish.

I stopped by AutoZone. They scanned the codes for me. Following is what I got:

P0171....System too Lean (Bank 1)

P0172....System too Rich (Bank 1)

So how is it too lean and too rich?? Did the computer try to make a change and over compensate or did having the battery unplugged reset something?

Thanks for any help or suggestions.

Doug

Reply to
drowland1967
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what did you get as a reply? I have a similar situation with a C70 2001

Reply to
richgannon12

No replies yet...

I did have a little more info. I was getting the oil changed the other day. The guy there offered to hook it up to their code scanner. It was a nice one. He was able to see the voltage coming off of the O2 sensors and the MAF sensor. You could see the O2 Sensor voltage changing. The MAF sensor voltage wasn't changing at all. he said this seemed to suggest it was the MAF sensor that was bad... I plan to swap it, but I haven't had time.

Does anyone know what the MAF sensor should look like on a scanner like that?

Thanks, Doug

Reply to
drowland1967

OK, I changed the MAF sensor. The car seems to run a little better. The Check Engine light is still on. It still doesn't run like it did before. Not sure what my next step should be...

Any ideas?

Reply to
drowland1967

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