What info does MB computer tell you when plugged into your car

Shanusacarabus

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Just a general thought i was having really, i own a 2000 W203 and its coming up to its first service since i got it.... i think they will plug it in but i just wondered what these computers see/tell us ???
 

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They tell you of any fault codes logged on the car, that is the first thing that anyone looks for. They can be erased if there are any, and after a short drive the car can be re tested to see if any come back, this being the case they are permanent faults.

MB garages do not put the car on STAR when going in for a normal service
 
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Shanusacarabus

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Fault codes as in what though... like for example can it tell u your gearbox is on its way out.... or engines not running well.... can it tell u what parts need changing ect, also if they dont check it as part of a service then when would they check it ??.

Sorry to be a pain Malcolm... as always lol
 

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You cant tell if something is on the way out, only if a fault has been logged.

For instance if the MAF was going down, it may have entered a Co2 sensor fault into the memory, then the operator has to be wise enough to know that it was the MAF that caused the fault code. You may have a coil pack on the way out,,and it will have recorded this. It can only record faults that are electronic, or items that have an ECU
 
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Shanusacarabus

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Grrrrrr i hate being rubbish .... whats a MAF...... i would say is a Main Air Filter but i dont want to be laughed at.... doh... too late !!!
 

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Grrrrrr i hate being rubbish .... whats a MAF...... i would say is a Main Air Filter but i dont want to be laughed at.... doh... too late !!!

You were spot on,, but Mass Air filter
 
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Shanusacarabus

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But im guessing its not the paper filter ??? lol.... Maybe i should just buy a W203 haynes manual haha
 

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They tell you of any fault codes logged on the car, that is the first thing that anyone looks for. They can be erased if there are any, and after a short drive the car can be re tested to see if any come back, this being the case they are permanent faults.

MB garages do not put the car on STAR when going in for a normal service

Mine does - they show me the fault/software print-out at the handover?
 

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Mine does - they show me the fault/software print-out at the handover?

Not many do,,if you ask for a read out, they charge up to £75
 

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You were spot on,, but Mass Air filter

Malc,
Nit picking but technically isn't it the Mass AirFlow Sensor? After all, there's no filter in it.
I've often wondered what MAF actually means as MAS, AMS all seem to mean the same thing but MAF never quite tied up with the acronym. Is there actually such a thing as a MAF?
Odd what you wonder about when you're bored at work!!
cheers
JB
 

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Malc,
Nit picking but technically isn't it the Mass AirFlow Sensor? After all, there's no filter in it.
I've often wondered what MAF actually means as MAS, AMS all seem to mean the same thing but MAF never quite tied up with the acronym. Is there actually such a thing as a MAF?
Odd what you wonder about when you're bored at work!!
cheers
JB

Well MB call it a filter,, you can pass an electronic signal through a filter. In the case of the MAF, the air is passed over a sensor, and in a way it is filtering, but only in a way as it does not alter that air flow, its a kind of backwards, as the sensor sets up the fueling, and not the air flow.

I will take a look at MB's description
 

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OK I have the answer, the F is for FLOW not filter, so I have been wrong in using that word, although it is still called a MAF.

So thank you JB, thats another ice cream with 3 flakes that I owe you ;):D
 

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We actually bunch a number of disfferent things together under "MAF".

The early ones were technically "hot wire mass air flow sensors" and then the later ones are "hot film mass air flow sensors" (which is where "HFM" comes from in the merc description of the fuel system in the M104 engines etc).

Both measure the mass of air flowing past by how much it is able to cool a heated element - therefore removing the inaccuracy of the previous devices (that just measured deflection of a plate by the breeze flowing past) caused by air density changes with variations in elevation of the car.

The change to the film type being an attempt to remove the contamination "whiskers" issue, the need for the very hot burn-off wire heating cycle and the extreme fragility of the wire models.

Within the hot film models, later ones incorporate the IAT (intake air temperature) functionality to measure the temperature of the airflow, so removing the need for a separate sensor and simplifying the loom.

Bosch have some useful PDFs showing the various generations and their voltage output curves against the mass or air flowing past (can be used to check correct operation with a meter).
 

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Bosch have some useful PDFs showing the various generations and their voltage output curves against the mass or air flowing past (can be used to check correct operation with a meter).

Yes they can be checked with a meter, but if you do not have a break out box it is very hard to get to the connections to do the test
 
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Shanusacarabus

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Hey can i interupt yr little discussion hahaha.... just looked at my engine and apart from finding the air filter that has more dust..sand flies and leaves than i have in our local forest i couldnt see this " MA filter/flow " hehehe... do you know where it is on my 2000 2.0K ???
 

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Hey can i interupt yr little discussion hahaha.... just looked at my engine and apart from finding the air filter that has more dust..sand flies and leaves than i have in our local forest i couldnt see this " MA filter/flow " hehehe... do you know where it is on my 2000 2.0K ???

2000 2.ok what car in the range is it please
 
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Shanusacarabus

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Mines the W203...... i looked at your guide too Alan but mines different to that
 

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Thought it would give you a rough idea what to look for, somewhere between the air filter and the inlet.

I cleaned mine with carb cleaner, make sure you don't touch the thin wire with your hands.

Alan
 

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