P0170 and P0173 codes

dms58 · 01-20-2008, 10:39 PM

Hello,

My 98 ML320 has been giving me P0170 and P0173 codes. It has 78,000 miles. I cleaned the MAF and reset codes. They immediately came back. Then replaced the MAF and the CEL went out and codes went away temporarily, now they're back. Any suggestions on the next course of action. Truck seems to run fine.

Thanks! I have gained incredible knowledge about this truck from this forum. Much appreciated!

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mihir_d · 01-21-2008, 01:57 AM

Quote:

Originally Posted by dms58

Hello,

My 98 ML320 has been giving me P0170 and P0173 codes. It has 78,000 miles. I cleaned the MAF and reset codes. They immediately came back. Then replaced the MAF and the CEL went out and codes went away temporarily, now they're back. Any suggestions on the next course of action. Truck seems to run fine.

Thanks! I have gained incredible knowledge about this truck from this forum. Much appreciated!

99% of the times it is the MAF that causes these codes, but if its not the MAF, it could be also the oxygen sensors or spark plugs. They all play a role in fuel adaptation...

PaulX608 · 01-21-2008, 05:03 AM

Don't forget the fuel filter. You can't expect fuel to be metered consistently if it can't be delivered consistently.

mihir_d · 01-21-2008, 12:35 PM

Quote:

Originally Posted by PaulX608

Don't forget the fuel filter. You can't expect fuel to be metered consistently if it can't be delivered consistently.

Fuel filter, Fuel pump & Fuel pump relay/fuse...check all of those...

dms58 · 01-21-2008, 08:22 PM

Thanks guys,

The spark plugs were replaced 2 years/14,000 miles ago. It's been 4 years/28,000 miles since the fuel pump and filter were replaced. I guess the fuel filter would be a good place to start. Then I'll probably replace the O2 sensors.

Anyone know how difficult the Fuel Filter replacement is? The fuel pump has been upgraded.

PaulX608 · 01-21-2008, 09:39 PM

Do a search, it's been discussed quite a few times. Remove the left rear wheel and plastic fender liner, you'll see it.

roberthelfrick · 01-22-2008, 03:17 PM

You are sure of the quality of the replacement MAF sensor? Is it rebuilt, a proper insert, or OEM complete piece?

Dhaval Katharot · 10-15-2009, 11:13 AM

Dear Friends,
I had same codes come up on my 2001 ML320, which has 72,000 miles on it. It was kindda on and off, it will come on for a day or two and then automatically go off for a day or two. i drove about 1500 miles in this conditions. Then finally one day took it to autozone to read the codes. They said P0170 and P0173.
I searched on this site and found that many had tryed MAF cleaner, i thought to give it first try. I went to Merc. dealer and brought a new airfilter and then a MAF cleaner from autozone. and it just took me few minutes to change the airfilter on ML. Then i took out MAF sensor and sprayed almost half bottle of MAF claener on it. Let it dry for 20 minutes and fixed everything back.
Started car and check engine light was there, i shut engine 3 times and restarted 3 times, but Check Engine light was still there. I thought may be something else is wrong. But next day after about 3 trips of 5 miles, Check engine light went off. and it has not come back since last 15 days now. I noticed ML also increased pick up because of new airfilter. So i would sugest that please before you spend lots of money on expensive MAF sensor, just give try to new airfilter and clean your MAF sensor with it's cleaner available in autozone. I will keep posting here in future, may be after 1 more month to notify that light has come up again or not. But for now i am very happy that it has not come again since 15 days.... touch wood.
Thank you,
Dhaval Katharotiya
ML320 and BMW 750iL.

01-21-2008, 05:03 AM	#3
PaulX608 Super Member 2001 BMW 7-Series My Garage Join Date: Jul 2005 Location: Manassas, VA, USA Posts: 718 Drives: 2001 740iL, 2004 ML350	Don't forget the fuel filter. You can't expect fuel to be metered consistently if it can't be delivered consistently. __________________ Paul X Danner NRA Life Member M-B Owners Gun Club, Member #13 Email 2001 ML430(sold) 1993 400E(totaled) 1999 C230(sold) 2004 ML350(the mrs.) 2001 BMW 740iL(mine)

01-21-2008, 08:22 PM	#5
dms58 Newbie Garage is empty, add now Join Date: Dec 2007 Posts: 5 Drives: 1998 ML320	P0170 and P0173 codes Thanks guys, The spark plugs were replaced 2 years/14,000 miles ago. It's been 4 years/28,000 miles since the fuel pump and filter were replaced. I guess the fuel filter would be a good place to start. Then I'll probably replace the O2 sensors. Anyone know how difficult the Fuel Filter replacement is? The fuel pump has been upgraded.

01-21-2008, 09:39 PM	#6
PaulX608 Super Member 2001 BMW 7-Series My Garage Join Date: Jul 2005 Location: Manassas, VA, USA Posts: 718 Drives: 2001 740iL, 2004 ML350	Do a search, it's been discussed quite a few times. Remove the left rear wheel and plastic fender liner, you'll see it. __________________ Paul X Danner NRA Life Member M-B Owners Gun Club, Member #13 Email 2001 ML430(sold) 1993 400E(totaled) 1999 C230(sold) 2004 ML350(the mrs.) 2001 BMW 740iL(mine)

10-15-2009, 11:13 AM	#8
Dhaval Katharot Newbie Garage is empty, add now Join Date: Oct 2009 Posts: 1 Drives: ML 320	P0170 and P0173 on ML320 Dear Friends, I had same codes come up on my 2001 ML320, which has 72,000 miles on it. It was kindda on and off, it will come on for a day or two and then automatically go off for a day or two. i drove about 1500 miles in this conditions. Then finally one day took it to autozone to read the codes. They said P0170 and P0173. I searched on this site and found that many had tryed MAF cleaner, i thought to give it first try. I went to Merc. dealer and brought a new airfilter and then a MAF cleaner from autozone. and it just took me few minutes to change the airfilter on ML. Then i took out MAF sensor and sprayed almost half bottle of MAF claener on it. Let it dry for 20 minutes and fixed everything back. Started car and check engine light was there, i shut engine 3 times and restarted 3 times, but Check Engine light was still there. I thought may be something else is wrong. But next day after about 3 trips of 5 miles, Check engine light went off. and it has not come back since last 15 days now. I noticed ML also increased pick up because of new airfilter. So i would sugest that please before you spend lots of money on expensive MAF sensor, just give try to new airfilter and clean your MAF sensor with it's cleaner available in autozone. I will keep posting here in future, may be after 1 more month to notify that light has come up again or not. But for now i am very happy that it has not come again since 15 days.... touch wood. Thank you, Dhaval Katharotiya ML320 and BMW 750iL.

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01-22-2008, 03:17 PM	#7
roberthelfrick Junior Member Garage is empty, add now Join Date: Jun 2006 Posts: 25 Drives: 2000 ml320 1986 560sel 1973 280se4.5	You are sure of the quality of the replacement MAF sensor? Is it rebuilt, a proper insert, or OEM complete piece?

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