MAS/MAF failure rate.

[oigle]

A general question. Have noticed on this forum a lot of issues relating to MAF sensors or MAS, whichever way you choose to call them.
Are these articles to be treated as a service issue - in other words, do they have a life? Does everyone have trouble with them eventually and how long is the service life normally. My vehicle is an ML270 2003 production.
I ask because I do a lot of outback travel and wonder if I should carry one as a spare. Have done 75000km so far with no sign of problems but don't want to get caught. Have a 15000km trip coming up in October and a lot in outback country.
Some of you guys do Merc servicing and might have an idea as to how often they fail.

 

[Ellsy Tanners]

Have a 15000km trip coming up in October and a lot in outback country.

Lucky bugger!! Thats one think id love to do, explore the outback!!


Its true that the Air Mass Sensor is the single most common cause of running problems on mb's.

So if you dont mind the expense of buying it and having it sat there waiting to be used, then its not a bad idea. There is the possibility you may never need it. Service life is hard to say, A friend of mine works in dubai and seems to change them like under wear!! I dont tend to change to many, as most of the cars i see are less than 3 years old, yet i still do change them.

You will need to carry a small tamper proof trox tool to be able to change it on the move.

Bear in mind a air mass fault very rarely causes a total break down, so you should still be able to make it home even if it fails, all be it with reduced power.

The choice is urs you great gallort!! ( got to love Alf Stewart!! ).

See what some of the other guys think as well, they may well agree or disagree with me.

Good Luck ( ya flaming mongrel)

 

[brandwooddixon]

Had mine replaced at 40k miles. The car is onow on 125k miles and I haven't experienced a MAF failure again.


Probably will tonight now though!

 

[psmart]

Hi Oigle,

Carry a spare, as they go out of spec, as I discovered 2 weeks ago when I ran the diagnostics whilst trying to figure out my gearbox problem. It had not failed and was producing very plausible results, but only a trained eye would be able to realise the values were not correct. Obviously, Im not a trained eye, but I spotted occasionally that the MAF would give 'Unspecified values', so I replaced it to eliminate a possible cause for the gearbox problem.

I did notice prior to replacing it that the mpg was not as good, and that the 100-115mph speed range was sluggish (autobahn work), but after changing the MAF, Im getting excellent economy again and the gearchange is very smooth and the pulling power of the car is uniform.

It looks like the MAF maybe constructed with Thermistors, probably 2 in a wheatstone bridge. Thermistors are known to age and go out of spec, so on this alone, its worth replacing.

My ML is 12.2000 and has done 83K. I cleaned the MAF at 60K and I probably noticed the reduced mpg around 75K.

 

[oigle]

Thanks guys.

I notice it is often mentioned, too, that Bosch can supply at a much cheaper price than MB. As I haven't disassembled mine, I don't know if the Bosch part number is displayed on the unit.
Does anyone happen to have the appropriate part number at hand to save me pulling it apart to determine same?
I think, provided price isn't too steep, I'll carry one as a spare. I'm aware that it can limp home without it working properly but I pull a 1600kg caravan and that would not be nice on hills!!! Not that we have BIG hills in Oz - and even more so in the outback!! We are going to drive the Nullabor Plain across the south of the country to Perth. It has a couple of interesting points - the longest straight bitumen sealed road in the world - 146.6km and flanks the railway which has the longest straightsection of rail track in the world - 478km. The head of the Great Australian Bight also has the longest stretch of uninterrupted limestone coastal cliffs in the world - the distance escapes me. Should be an interesting trip.

Thanks for the tip re special tool too - hadn't looked at that.

 

[oigle]

Just asking again - has anyone got the Bosch part number for the MAF sensor for a 2003 ML270??
The question was buried amongst other stuff in my last post.
Anyone??

 

[BlackC55]

Its a Peirburg part not bosch.

I replace at least 2 a week.

 

[oigle]

Its a Peirburg part not bosch.

I replace at least 2 a week.

Thanks for that.
Do you buy them from Peirburg or MB? Is there a big difference in price? Not sure if Peirburg operate in Oz. Will have to check. Does any particular international group sell Peirburg?
I have yet to check the MB price here. Maybe I'd better start there!!

 

[oigle]

Its a Peirburg part not bosch.

I replace at least 2 a week.

Further to my post, I have found a Pierburg parts supplier here in Oz. Looking through their catalogue, it seems part number 7.22684.07.0 applies to the article required. Have asked for a price by email - no answer yet.
Does this part number seem correct to you for the ML270/2003 model? Wouldn't want to order a wrong part!!
Thanks.

 

[jimsinessex]

You will need to carry a small tamper proof trox tool to be able to change it on the move.

BEWARE - the security Torx screws on my MAF sensor are a 5-pointed star with central hole NOT the usual 6 pointed star with hole.

This caused lots of head scratching as I couldn't see why the normal security bit wouldn't fit. The last thing I thought of checking was the number of points!

Jim

 

[psmart]

I'll split my MAF tomorrow when I get back to the ML and see what part number, if any is written on it (ie. non-Merc part number). I bought Merc and it cost EUR89 in Austria, thats with 20% VAT, so not too pricey.

On the ML, I found it easier to undo the 3 air-filter bolts, pull the air filter slightly forward, then undo the two MAF screws.

 

[oigle]

I'll split my MAF tomorrow when I get back to the ML and see what part number, if any is written on it (ie. non-Merc part number). I bought Merc and it cost EUR89 in Austria, thats with 20% VAT, so not too pricey.

On the ML, I found it easier to undo the 3 air-filter bolts, pull the air filter slightly forward, then undo the two MAF screws.

Let's know what you find psmart. Appreciate your input.

 

[oigle]

BEWARE - the security Torx screws on my MAF sensor are a 5-pointed star with central hole NOT the usual 6 pointed star with hole.

This caused lots of head scratching as I couldn't see why the normal security bit wouldn't fit. The last thing I thought of checking was the number of points!

Jim

I'll see if I can find the correct one. Thanks.

 

[psmart]

Part numbers on the MAF are:-
Mercedes = A611 094 00 48
Pierburg, Germany
PBT-GF30
7.22684.00
LM 0028
On the top rim is typed 29000137.S1

Loks like the part number is PBT-GF30 but go armed with the other numbers to your supplier just in case.

Good luck on your adventure

 

[oigle]

Part numbers on the MAF are:-
Mercedes = A611 094 00 48
Pierburg, Germany
PBT-GF30
7.22684.00
LM 0028
On the top rim is typed 29000137.S1

Loks like the part number is PBT-GF30 but go armed with the other numbers to your supplier just in case.

Good luck on your adventure

Thanks mate. Will now do a local price comparison. The part number quoted here by Piermont had a different suffix - .07.0 instead of .00. Wonder if there has been an update?? Will check with them.

 

[oigle]

I'll split my MAF tomorrow when I get back to the ML and see what part number, if any is written on it (ie. non-Merc part number). I bought Merc and it cost EUR89 in Austria, thats with 20% VAT, so not too pricey.

On the ML, I found it easier to undo the 3 air-filter bolts, pull the air filter slightly forward, then undo the two MAF screws.

Have obtained some prices. Think you guys are better treated than us. Price from MB is Retail AUS$324.90 (170 pounds or 194 Euro). Price for Club members AUS$260 or 140 pounds or 156 Euro.
Piermont offered theirs for AUS$241, which was a bit cheaper.
Inquiry at MB tells me they have sold one per month for the last 3 months and then none since last November. Seems the failure rate here isn't as bad. Perhaps prevailing weather conditions may have an effect. On the basis of the above, I think I'll take the risk - can always just wait for a part to be airfreighted in if it is necessary. They carry them in stock which is good.
Thanks for help.