Knock Sensor needs replacing exhaust - quoted £1200!!!! :(

[andyjbutt]

Morning, after the transmission light came on on my CLS 220d I ran mine through Autel MB diagnostics and it came out with fault codes P229F62 and P220162 against VIN WDD2183012A169379. I think this is the same OM651 engine that others have had NOx sensor issues with. Is this likely to be the same issue - faulty NOx sensors needing replacing and software update?

Legally speaking I think there is a strong case to argue that if MB redesigned components they did so to avoid a known issue / design flaw. The sale of goods act covers at least a 5 year period so worth discussing with MB customer services I think?

 

[andyjbutt]

Also as an after-thought has anyone tried cleaning them?

 

[BlackC55]

Also as an after-thought has anyone tried cleaning them?

That wont work.

 

[kravena]

I know this is an old thread, but I've got a 2015 C250D W205 with the code P229F62, which turned out to be a clogged Adblue injector, and what I found on the internet did not link the two issues. Everywhere that I read on forums and so on, said this was a faulty sensor, when it wasn't.

For anyone with this code, check this video first

To view this content we will need your consent to set third party cookies.
For more detailed information, see our cookies page.

Accept third party cookies

, just use clean water and make sure you don't push any of the crystals into the exhaust box.

If you do need to replace the NOx sensors, they will need a teach-in to reset the calibration. I used a MaxiCom MK808BT, which was recently updated (~ June 2022) to allow calibration of the NOx sensors, just make sure you update the software on the Diagnostic kit.

I replaced the NOx sensors before checking the Adblue injector, when I should have done that first.

You don't need to remove the Adblue injector from the car, just fill a cup with water and dip the end into it and keep shaking until it's clean, as the Adblue dissolves in water. If you remove the injector from the car, you'll just spill Adblue everywhere.

And lastly, this should be part of the service check from Mercedes, as this was completely blocked on my car.

 

[BlackC55]

This is also an issue that we see quite a bit. Together with NOX sensor issues, pumps, leaky tanks etc etc. Biggest pain in the ar$e that adblue system.