Advice on cleaning lambda (O2) sensors

[LP670]

Hi all, my car struggled to get through the emissions test on a recent MOT and the tester suggested cleaning the Lambda sensors. Im just wondering what the best way is to go about cleaning them, a quick google gave numerous ideas one of the most popular seemed to be cutting a lemon in half and sticking the sensor into it! Has anyone tried this method with success or has any other suggestions?

[stevieturbo]

Try the dishwasher ?

[E-bmw]

Buy replacements.

[anonymous-user]

The only thing that could (but is unlikely) to help is a good old italian tune-up! Get the sensor nice and hot to burn on any contamination. But frankly, if the sensor is that contaminated 1) it's probably dead and 2) your engines probably so knackered it won't make any difference.

[GreenV8S]

E-bmw said:

Buy replacements.

^^ That. But it's possible to test them to see whether they're getting blocked. I guess you're talking about narrow band sensors, in which case you should see the signal cycling between rich and lean about once a second while the engine is in closed loop mode, if everything else in the engine management system is in good order. The main symptom of a dirty sensor is that it cycles more slowly.