Check Engine Light with code PO173
 

I am new to the site and my wife has had the car for 6 months. It is a base 2005 model with 16k on the clock.
I was wondering if the diagnostic code of PO173 meant that one of the 4 oxygen sensors might need replacing? The dealer wants to do more tests but gave me the information of Fault Code PO173 - Fuel System - Control Over Limit - Oxygen Sensor 1 Bank 2 - Burning Ritch - will require further diagnostics.
To be honest I hate the dealers and their high prices. Apparently I had put some poor fuel in the car and so i ran the system to just under a quarter and filled up with Premium Esso. The Check Engine Light stayed off for 47 miles and has come on once again. Does anyone know what Oxygen Sensor to replace with the info above?
Thanks
GT

Re: Check Engine Light with code PO173
 

There are quite a few pages in the service manual bout the P0173 code, but here is the summary :

https://cimg6.ibsrv.net/gimg/www.cro...3170967a86.png

You can download the service manual from the below link and read all about the troubleshooting procedure.

How the heck did a Crossfire find it's way to the Cayman Islands ?

Re: Check Engine Light with code PO173
 

Try cleaning or replacing your mass air flow sensor first.

Re: Check Engine Light with code PO173
 

Thanks for the info - although not too sure where to start. The car was shipped brand new back in early 2006 and spent a lot of its life sitting in a garage unused hence the 16K.
Do i need to let the dealer further it's diagnostic tests on the car?
Thanks

Re: Check Engine Light with code PO173
 

This should help:
http://www.benzworld.org/forums/atta...low-slk320.pdf

Re: Check Engine Light with code PO173
 

I would not take a Crossfire to a Chrysler dealer for anything other than reprogramming of the Tire Pressure Monitor Sensors. Of course, where you are, you may have no choice. Is there any small independent garage known for Mercedes expertise you can go to? You are, after all, driving an SLK320 with a different body - what is under the body is all Mercedes SLK320 (SLK32 AMG if it is an SRT).

Re: Check Engine Light with code PO173
 

I know the car had some poor fuel a month ago and before we bought it the fuel pump was replaced. I am wondering why when the light was reset it came back on after 47 miles. Maybe the poor fuel is still in the system? Just wondering what steps i take first to minimize expense. The car runs extremely well so no problem with performance.

Re: Check Engine Light with code PO173
 

It means the problem still exists
It may take 25 to 47or more miles for the system to fault and set off the CE light.


Mine is doing that now but I don't have time to get under it and replace the O2 sensor. Until I get some downtime at work mine is a garage queen.


I am also running lean and it sometimes happens at idle. So it very well could be the bad fuel has clogged and injector or a filter.

Re: Check Engine Light with code PO173
 

According to the Mercedes forum, the most common issue for the P0173 is a failing mass flow air sensor. I believe the OEM Bosch part is $145 from Autohaus or $100 on Amazon:
https://www.amazon.com/Bosch-0280217...sch+0280217515

Re: Check Engine Light with code PO173
 

Agreed,
I'm on my third one at less than 60K on the clock


Yeah it is common.