Author Topic: Upstream Lambda Sensor  (Read 355 times)

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Offline knghtandyk

  • S Class
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  • Posts: 2
  • Gender: Male
  • Engine: 2.2L
  • Fuel: Diesel
  • Transmission: Manual
  • Trim: TS2
  • Year: 2011
Upstream Lambda Sensor
« on: April 19, 2021, 01:18:05 pm »
Hi all,

I've been working on my 2009 Mazda 6 2.2 163bhp over the last year of lockdown and with the exception of a niggling P0133 error that keeps cropping up, it's starting to come together nicely.

The error I'm getting is a P0133 02 sensor circuit slow response for bank 1 sensor 1, which normally I'd read as being a pre-cat O2/lambda sensor.  I've found quite a few O2 sensors for the GH/R2AA models on ebay that claim to be compatible, and I've just ordered one I've had confirmed as being a replacement for the O2 sensor I've located which is post cat/DPF.

Thing is, I can't track down a pre-cat O2 sensor on my car for love nor money, either through searching for documentation on various forums or from physically searching the exhaust (I've just replaced the turbo and have gone the length of the exhaust from there back).

I've seen a single post in another forum where someone states this engine doesn't have an upstream, only the downstream post-cat.  Can somebody confirm that 100% or point me in the direction of the sensor if there is one please? 

Thanks a lot in advance!

Offline knghtandyk

  • S Class
  • *
  • Posts: 2
  • Gender: Male
  • Engine: 2.2L
  • Fuel: Diesel
  • Transmission: Manual
  • Trim: TS2
  • Year: 2011
Re: Upstream Lambda Sensor
« Reply #1 on: April 23, 2021, 08:13:16 am »
Update for anyone else in the same situation - I replaced the post-dpf O2 sensor with a Blueprint version - ADM57064, having also had the fuel filter swapped out.

During swapping the sensor I realised the new one has a sealing washer while the old one didn’t and from reading the specs for the P0133 code, an exhaust leak in the vicinity of the sensor is one of the potential causes.  It’s possibly too early to tell, but the car’s done 30+ miles now without the P0133 coming back up and the engine feels quite a bit smoother as well.