Mercedesdiesel

So the voltage should be reading in between 11v and 14v? Is that correct? And if it’s under or over that range then I have to replace the entire MAF is that correct? (This whole piece is under warranty for another two months since I replaced it 10 months ago)

also, my new mechanic said it could actually be an issue with my ecu. Do you think is a reasonable diagnosis? I thought if it was my ecu being faulty more codes would come up.

Maj. Dundee

No, the voltage can be no less than 11v and no greater than 14v.

What whole piece is under warranty.? Remember you have two MAFs that must be tested.

ECM is bulletproof. The problem is under or over voltage. It could be a battery or alternator problem.

Mercedesdiesel

The whole Y Pipe was replaced. They told me this was the MAFs that was replaced (both). So if there is a voltage issue. What should I be replacing? My MAFs again? Or should I be looking at my alternator or battery? My mechanic didn’t say there was any issues with alternator or battery.

Maj. Dundee

Why can't you perform the test that I provided you in post #21?

rrvtechcon

So if the test is satisfactory meaning 11- 14 volts reading for both maf sensors OK then what will be the next move to solve this fault code 150200. I am interested because I have the same issue too. I replaced MAF sensors and new air filters but still having this engine fault code 100800 - upper limit value of component B2/7 mass air flow sensor has been exceeded.

Maj. Dundee

Do you have both codes stored at the same time?

Did you delete both codes?

When you delete the codes, remove the key from the ign.,wait 20 secs., then check for codes again.

rrvtechcon

Thanks for your quick respond. Not yet, I am still waiting for the correct scan tool from Amazon. I just ordered icarsoft MB V2.0.

rrvtechcon

Maj. Dundee,
For diesel ML 320 bluetec, do you know if this resetting the quantity mean value adaptation is really required each time you replace the air filters and also the MAF sensor calibration to adaft the ECU to the new Maf sensors.

Maj. Dundee

Here is the reset procedure.

rrvtechcon

Thanks I will try, but I don't have problem with the Ad Blue system in fact I just replaced the defective Adblue pump and drain/replace the Adblue fluid last year.

tengraver

@Maj. Dundee I'm interested to see where this part listing for the individual MAF sensors came from. Can you direct me to it? All I've seen is the complete snorkel with both MAFs included for $360. I'm enjoying this thread because I have similar problems with my 2009 ML320 Bluetec. I've had the 150300 code since I first changed air filters and sealed up all the air leaks. I also have a P0101 code that I guess corresponds to it. It could be coincident that a sensor went bad at about the same time I did the service work but it just seems unlikely. I have not tested the voltage on the sensors yet since I don't have access to the car at the moment. I'm also interested in the procedure you listed to reset the AdBlue - would this also be necessary when changing air filters? (AdBlue was deleted on this car by the previous owner and has never caused me any problems.) Thanks in advance.

Maj. Dundee

[QUOTE=tengraver;8028437]@Maj. Dundee I'm interested to see where this part listing for the individual MAF sensors came from. /QUOTE]

What post # are you referring to?

tengraver

[QUOTE=Maj. Dundee;8028705]
#34 for the reset procedure, and #6 for the parts diagram.

rrvtechcon

I do not think the Adblue reset has something to do with the engine air filter replacement but an ECU reset called value adaptation which can only be done using MB star scan tool. This is an expensive scan tool so you will end up going to the MB dealership to calibrate your ECU to adaft to the new air filter or new MAF sensor. If you do not do this then you will have that fault code keep coming back.

tengraver

Yeah, I don't do stealerships. I worked for too many of them to trust ANY of them. CELs don't keep a diesel vehicle from passing inspection in my state so I am ok with ignoring the CEL so long as my mileage and performance don't suffer. I think it's awfully petty for a company to make their vehicles so difficult to service that you can't even change air filters without their blessing. I probably bought the wrong car...but I'm stuck with it for now.

tengraver

The voltage readings were almost exactly 12v for BOTH sensors.....stumped.

Curious about the left/right installation of these sensors....original alignment on mine was that one is right side up and the other is upside down. That seems to make sense so that the air flow across the sensors is in the same relative direction. I can't tell from the pics I've seen if this is the case or not. Any words of wisdom in that regard? I'd hate to think that my problems are due to something as simple as a sensor installed upside down!

rrvtechcon

Although I do not feel any effect on mileage, power & idling but then is there any long term bad effect from this fault code if I just ignore it? anyway our province in Canada is not strict too. My only problem is that strong burnt diesel smell from the exhaust pipe usually in the morning at idling but no such smell in the engine compartment or inside the cabin that I will suspect leaking fuel injectors, other than that it is running normal. I did lots of work & test already but did not find any intake leak or EGR or NOX & O2 sensor problem. Unfortunately, end up replacing MAF sensor and engine air filters but still this fault code keep coming back. I am planning to buy or rent this icarsoft MBII upgraded version from Amazon which is the proper scan tool for Mercedes Benz in order to diagnose further on live data streaming. I was only using an Autel 490 which is only reading generic fault code P0101. I am very interested to discuss with you about this matter because I believed we have exactly the same vehicle 2009 ML 320 Bluetec.

tengraver

Yep, we do! I have the icarsoft mb....not sure which version but I bought it a couple years ago. It does show the 150300 code under BENZ and also the P0101 under OBDII. Maybe we can figure out how to rid ourselves of these problems together. I have recently gutted out the DPF and the catalyst cans and it brought my car back to life! But I still have the CEL P0101, along with a couple codes concerning DPF sensors. I am considering sending my ECU to Malone to have the DPF, EGR, AdBlue, and Swirl valve deletes, but that costs $700, which is money I don't have laying around, even though I own a MB, lol. Maj. Dundee seems to know these vehicles very well, but I haven't seen his response to any of the last few posts. Hopefully he will chime in and help us both!

rrvtechcon

Where you able to check each wires from ECU to MAF sensors meaning in addition to the 12V reading you must have also a signal voltage from MAF sensor to ECU about 3- 5 volts and also the ground continuity (procedure available on You Tube) if everything is OK then proceed on live streaming using your icarsoft MB II
check your MAF flow g/s reading @ idle/park around 5 - 10 g/s and at max load between 150 - 200 g/s for a good MAF sensor. If everything is OK then your MAF is good.
With regards to your DPF, have you try to modify your NOX & O2 sensor mounting so that the sensor end will move away from the gas flow. I think in some Auto parts supply in the state they sell this kind of adaftor but not sure if it will fit our vehicle. This way the sensor will not have any signal to transmit to the ECU that trigger fault code. I am interested to know how you deleted your DPF so next time I have problem with my Adblue system I can just delete it. I think deleting swirl flaps/valves and EGR procedure is also available in You Tube.

rrvtechcon

With regards to your sensors orientation or mounting to the MAF Y pipe, I believe it is correct because if you fit the other sensor the same position then you will have to flip your wire harness socket too which will make more tension on the wire harness, I do not know yours but my wire harness do not have enough slack. I knew this because before I replaced the whole MAF sensor assembly, I started trying to clean the old sensors using a MAF sensor cleaner/ spray but no luck then I decided to replace only 1 sensor with a good 2nd hand sensor available from Ebay but still did not work.

tengraver

@rrvtechcon: When I tried to check the signal coming out of the MAF sensors I blew a fuse. Obviously I didn't do something right but I was trying to follow a youtube that seemed reasonable. I need to see what my live streaming is for MAF on iCarsoft and compare to your specs....it seems like if I remember correctly that there is only one reading. I would think since there are two sensors there should be two readings and if they are not within some given percentage it would throw a code. I think that is exactly what the P0101 is measuring as "out of range." PP: I haven't tried any mods to the sensors in the exhaust stream. What I did (after asking Malone about it) was to cut open the DPF and the catalyst cans and knock out all the filter media in there...then weld them back up. It wasn't much fun but I got it done. The cans could be replaced with straight pipes but they are WAY too expensive when I already have pipes that connect everything anyway (that was my logic, anyway.) This was done in preparation to sending off my ECU to Malone - which I haven't done yet and maybe won't since it seems to be working so far. I had the MAF codes before I did anything to the exhaust so I don't think the two are related at all. The previous owner had done the AdBlue delete (at great cost) and I've never had any problem with it, but it is also deleted with the Malone tune. It may be easier to disassemble the exhaust system and then clean out the cans but I did it on the car. I would recommend disconnecting the battery and unplugging the ECU before doing any welding on the car...that's what I did anyway and it didn't fry anything.

rrvtechcon

Tengraver, be careful when back probing the wire harness socket in my case I used a small diameter pointed wire to back probe (not the inside pins but the back of the socket) and ensure not to touch the other wire when I hook up my multitester to avoid the fuse from blowing or otherwise worse come to worse damaging the ECU.
How long have you been having this P0101? (approx no of year /mileage) and did your icarsoft MB 2 was able to clear the code but keep coming back whenever you start again.
In my case, as soon as I replaced the MAF sensor with the brand new one from MB, I drove for two weeks (erasing the code before driving thinking it will eventually disappeared) around 1000 km and about 6 starts & stops but the P0101 keep coming back so I decided to go to the MB dealership for the 1st time in my life. By the way, I owned a Toyota vehicles and did not experience going to their dealership at all. So the MB technician did calibration of the ECU to adaft to the new MAF sensor and I was charged only 1/2 hour work so its OK. I am happy the fault code has disappeared but after 2 months when I was driving on a traffic jammed and the engine was hot the fault code came back. I went back to the dealer but this time they want to replace the engine air filter first before proceeding to the next move so I was angry because they can not warranty the calibration work so I refused to proceed for the repair work. I replaced the air filters myself even if it was only 12,000 km but still the fault code keep coming back. I saw an air filter replacement procedure from MB shop manual online that whenever you replace the MAF sensor or air filter you will need to calibrate/adaft the ECU or they called it value adaptation which require the MB star scan and also the MB technical specification for us to know the temperature setting of the sensor hot wire. I believed the technician has set the temperature lower so that in the summer time it will trigger this fault code. Anyway, this is my first and last with MB dealer. I have to do further research on how to calibrate the ECU to adaft to the new air filters. Have you check your icarsoft manual if you can be able to change the parameters of the sensors?

tengraver

@rrvtechcon: I've had the car a little over two years and have had the P0101 almost the whole time. I did run into the "reset adaptations" comment from other sources as well, but have never done it or found a way to do it with the icarsoft MBII. I'm not sure about adjusting any parameters for the sensors but I will be looking into that the next time I hook it up. Yes, the code can be cleared but will come back at the next cycle of the key. Two years ago the entire snorkel - sensors and all was $180 which I thought was ridiculous and I refused to pay that much.....oh, silly me! Now they're twice that much. Even though I doubt seriously that there is anything wrong with the sensors, I did find some knock-off's on ebay for $75/ea. I'll be doing some tests on the old sensors and I'll let you know what happens!

rrvtechcon

Lesson learned from me, do not buy old or even new MAF sensor until you have done all the electrical test it will be good if you can find wiring diagram of the ECU to the MAF sensor and check all the wires for continuity. I want to do this but I have difficulty finding which wires from the ECU are the wiring going to the MAF sensor and also still searching where this ECU is hiding. I was able to get that knock offs from Ebay for free because it took over 2 months to ship from Lituania and I got my money back from PayPal but after over 2 months I got the item from the mail. They ship it the cheapest shipping option. P0101 could be anything from a bad MAF to any inlet air leak from the air filter inlet to the turbocharger inlet and outlet to the after cooler inlet and outlet hoses to the engine inlet flaps valves. But since this is fault code 150300 therefore we will have to concentrate around MAF sensor only so I suspect if not the "value adaptation reset" then it will be the wiring harness problem.I hope we can eventually solved this problem.

tengraver

@rrvtechcon: So I just drove around a while monitoring the MAF readings on the icarsoft MBII. The units are lb/min (this is on the OBD2 side under "live data stream"). The units you listed are in gal/sec so I'm not sure how that compares. At idle it was about 2.4 lb/min. At 2000 rpm around 8 to 10, and under heavy load up to as much as 18. I reset the CEL (P0101) but it comes right back with the cycle of the key. Before I drove it I tried the Major's sequence in post #34 to reset stuff, and all it seemed to do was to put the car into a DPF regen mode....which is a real problem when the DPF can has been gutted. This happened to me once before and it seemed to stay stuck in regen mode and smoke and get terrible mileage until used the DPF regen function on the icarsoft MBII to reset it. It will ask if you have oil in the exhaust and if you answer affirmative it will say that it cannot regen the DPF. That seems to shut the process off. Crazy, but all very unsuccessful in trying to make this stupid 150300 / P0101 crap go away. PS. the new cheapo MAF sensors from ebay had NO effect whatsoever....so there's some more money down the drain - at least someone other than MB benefitted from it, lol.