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2002 ML500 Silver
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76 Posts
Discussion Starter · #1 ·
98 ML320 186,500

I have been beaten by my car throwing P0170 and 173. I replaced the MAF and after that swapped with a known good one to test. It is not the MAF. I ditched my K&N airfilter for a new stocker in case the MAF was getting fouled.

I have searched for vacuum leaks and found no split or leaking hoses.

I can clear the codes and drive around for days with no problems.

I drive to work, take a right into the driveway while decelerating ~20mph and BAM! it throws the code.

I reset the code, drive home and then back to work. I turn the same corner and get the light and same codes again. This is the third time at the exact spot.

The first time it happend, I had the window open and thought I heard a little pop, then the RPM changed.

What the heck!

So these codes may not be the MAF, rather a mixture problem? Would fuel sloshing in the tank cause these errors?

Any ideas on what to look for next?

Thanks,
Ed
 

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C9H9N Offensive Odor Exuder
2002 ML320, 2005 S430 4MATIC RIP, 2010 F150 Crew Cab
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11,382 Posts
The codes are definitely for the MAF. I cannot offer you any clues except you may have gotten a bad MAF. Where did you buy it and does it have a warranty? It has happened to people here, before.
 

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99 ML430 - 13 328i
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1,112 Posts
The spot where the codes pop up are at the Bermuda Triangle of your area...

Just check on the MAF again with a new one.
 

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2002 ML500 Silver
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76 Posts
Discussion Starter · #4 ·
Update from long ago. It was the EGR tube clogged. The MAF was fine but the MAF codes would always come up first. I cleaned the EGR tube and no problems for last 8k miles. The tell is when the check engine light comes on during deceleration.
 

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2002 ML55 AMG, 2005 Chrysler Crossfire Coupe Limited, 1999 C280
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4,714 Posts
Update from long ago. It was the EGR tube clogged. The MAF was fine but the MAF codes would always come up first. I cleaned the EGR tube and no problems for last 8k miles. The tell is when the check engine light comes on during deceleration.
Thanks for the heads up Pinballer.

I'm intrigued that the EGR tube (which usually sets code P0400) instead set the MAF codes you posted above.

Anyone have any ideas why?
 
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