ok got a check engine light and pulled a PO173 Fuel trim malfunction bank 2?? anybody help me out with this??? thanks MC

 

According to Wolfgangs website http://www.whnet.com/4x4/dtc.html

P0170 Fuel Trim Malfunction (Bank 1) ) check vaccum leaks first or
P0171 System too Lean (Bank 1) ) faulty MAF (mass air flow) sensor
P0172 System too Rich (Bank 1) )
P0173 Fuel Trim Malfunction (Bank 2) )
P0174 System too Lean (Bank 2) )
P0175 System too Rich (Bank 2) )

Check for vaccum leaks first or faulty MAF (mass air flow) sensor

 

My check engine light been on since last summer. I had the same code as yours. Mines also had P0171 for the MAF. So what does the P0173 mean? How do you check for vacuum leaks? I also read that cleaning the MAF will help. What is i do clean it. will i need to reset the engine light? or the light will go off by itself knowing the cleaner has done its job?

 

use a precision electronis cleaner for the maf....dont touch anything inside!! and for the vac leak i may just spray al little WD around and listen for the idle to raise up...hopefully leading me to the leak!!! I'll let you know!!! mc

 

You can clean the MAF it'll come back (CEL)....replace the MAF, they're about $200 on the bay shipped. They're $264 through www.autohausaz.com - shipped. Don't waste your time at the dealer, it's a ten minute job to replace. The MAF IS a common problem on MB's.

You can reset the CEL by either correcting the problem or disconnecting the battery; however, if the problem persists, the CEL will reilluminate.

 

well as you stated its a ten min job...even quicker just to try cleaning it.... its looked pretty dirty...so I soaked it, let it dry, and put it back..... time will tell.....it was worth a shot...

 

so I wasted my time and cleaned my maf and it looks like I maybe in the clear.....the ce light went out on its own, and it been a few days..... I still think I will pick a new one up...but now have the luxury of shopping around for a better price.... anyone find anything good????

 

Best price I've seen lately has been @ http://www.autohausaz.com/search/pro...0Mass%20Sensor, $230.24 with free shipping

 

you have the directions on cleaning it?

 

I got codes p0170 & p0173 on my ML430, cleaned the MAF, light went off. But, the LTFTs are both still high (+24.2%/+25%) and STFTs are 0-2% at idle, so it won't be long before the DTCs are triggered again.

I ran a test with an OBD2 logger and the MAF reads 0.502 lb/min (3.8 g/s) at idle, up to over 15 lb/min (114 g/s) at WOT, 5300 RPM. These numbers seem plenty high compared those for other vehicles I've seen, anybody know if they're reasonable for my vehicle? I just don't want to replace the MAF and find out it was something else.

STFTs are all over the place under varying loads but are at least as positive under load as at idle, making an air leak unlikely. Thanks for any thoughts.

 

Hello guys
I have mine check engine on out of the blue and I checked is Fuel Trimming Bank 1 & 2 and I found out is AMS...is there anyone know how to clean it before I replace it or if anyone know the correct instruction to clean it
Thank s for your help and time.....

 

Just checked Autohausaz. $200 (today,at least).

 

I don't have any check engine light on but while checking a full test with star diagnostic system at dealer we got the P0173-133 code
"Selfadapation of mixture formation ... at limit value"!

Question: Is the light broken? then why I don't have other alarm about that?
I order to duble check I put key in position 2 (engine stop) were most of the sytem lights like SRS, ESP,ABS, service brake are on but the engine light not!

It's an S320 MY2000.

 

Morning guys....
I have a thought that would it probably the check engine is on simply cz I forgot to clean up and wash my air filter...I had replace it 10K earlier and I used K & N and after I clean up and washed it last night and it seems like everything now back to normal...I havent open and clean up the MAF cz I figure if the MAF that broke then check engine will come out again...
I ll keep it post it....after few days try...thanks.....

 

was curious about the same thing.. Please keep us posted. My car won't pass smog until I get that CEL off.

 

Hello so far I ve been driving about 60 miles since I clean up the air filter and so far the check engine is off...
There is another way if just in case is pop again then I ll clean up my MAF using the MAF cleaner that you could get it in pepboys....
If that one still not working then I ll go ahead replace it...
I still believe is worth to check n clean the air filter n MAF before u replace it