My 2007 R320 started showing a check engine light and my STAR tool pointed to MAF problems. The code is 2645 RH MAF over limit. When I run the MAF test in STAR it says it is fine. I replaced the air filters, Oil cooler seals, Y pipe with both MAF sensors (I still have the old sensors), and the oil and air filters. After all of that I still have the code and the low MPG.

I am really not sure where to go from here.
I have seen the DPF pressure sensor referenced as a possible problem
Even though STAR says the MAF sensors are fine I have thought about swapping out for an old one

Anyone have any ideas?

 

Since you have STAR, this thread may be helpful:
http://*******.com/Thread-ML-164-DTC...ue-above-limit
, even though a pre-DPF vehicle is referenced (maybe, not sure).
Idea here is multiple changes of air filters over time, without doing the adaptation afterwords, can set the code.
And, solution would be to go into DAS/STAR and reset live values for the error to 0.

Other possibilities:
- EGR malfunction, since the MAF+MAP is used to help measure how much exhaust gas is reintroduced.
(Total intake volume = fresh air + exhaust, MAF is used to match requested EGR to actual/calculated)
- Check boost/inter-cooler hoses and connections for split/leakage/greasy/whistle, the leaked air will be in the MAF
measurement, but not into the cylinders

Good luck, and please post your findings!

 

Just buy another Maf Sensor and replace... https://www.autohausaz.com/ is where i get my parts from good prices on OEM

 

I ran all the reset and learn values items under adaptations and the error disappeared for a day. I got a new error about MAF drift and so I did the reset and learn again. And it seems clear. I would avoid doing the reset and learn when it's 100f outside. I am hoping there was some non linearity that it couldn't account for being so hot out and the engine being so warm. I will pay off it comes back again.

 

From what i remember Maf on these benzes dont last forever..on the E320's these were so common on having to be replaced..

 

This one is the whole y pipe. You can't buy the sensors separate.