Light after O2 sensor change?

upstate NY · Post by **upstate NY** » 05 Feb 2011, 21:25

A couple of weeks ago I had a code for the O2 sensor, bank 1 sensor 1. Along with it came 14 mpg, and a strong fuel smell through the vents. I replaced the front O2 sensor. The smell went away and it seems as though my mpg have improved a bit. The light came back on today with the same code, any ideas?

Post by **jblackburn** » 05 Feb 2011, 21:46

What specific code?

Many times, O2 sensor codes are caused by a vacuum leak somewhere.

Post by **Ozark Lee** » 05 Feb 2011, 21:47

Codes?

What O-2 sensor did you use as the replacement?

The OEM Bosch are always fine, the Bosch universals have had mixed results but I think that is because of the funky splice box. Beyond that you are in uncharted territory with the aftermarket stuff - they rarely work correctly.

...Lee

upstate NY · Post by **upstate NY** » 05 Feb 2011, 21:51

I originally had P0133 bank 1 sensor 1, I replaced it with the OEM Bosch direct connect.

Post by **jblackburn** » 05 Feb 2011, 21:55

Has your gas mileage/performance improved at least?

P0133 is probably being thrown because the rear O2 sensor is old as well, and elicting a slow response.

Anyone ever tell you how picky and random these cars are?

upstate NY · Post by **upstate NY** » 05 Feb 2011, 22:00

Ya when I took it to the volvo dealership I use to work at, he reset my light and told me that my rear sensor was throwing a code. My mpg has improved a little, I would say 300 to a tank. I really need to figure out what else I can do to bring it up a little more.

Post by **jblackburn** » 05 Feb 2011, 22:08

300/tank for city driving sounds about right. At best, I have gotten 400 on a tank of solely highway driving - and then I was completely on E. The N/A's are said to get much better, though.

I would start by cleaning your mass airflow sensor and doing a thorough check for vacuum leaks. If it then continues to throw "slow response codes" (P0133), the rear sensor will need to be changed out as well. Usually the rear sensor has no effect on the way that the car runs, but this is one of the cases where the 2 sensors are fighting with each other.