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What is the correct maf sensor signal wire voltage at idle?
2001 330ci manual m54 turboed

Getting a maf code p0102 maf sensor low circuit voltage
Only code coming up
New maf sensor
Throttle doesn’t do anything
 

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2004 330Ci 85k miles
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It might be easier to determine if the MAF sensor value is correct or not by what you see using an OBD app, like OBD Fusion (see link below).
We typically see around 3.25 g/s at idle (700 RPM) with all accessories off.

If the MAF is not genuine BMW or Siemens/VDO branded, then it’s probably crap.

Your turbo may be affecting the situation if you don’t have a custom tune.
 

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Hard to tell an exact number as it depends on atmospheric conditions like pressure, humidity and temperature. Equipment with high load like electric fan, air conditioning, headlights and so on will also influence the airflow as DME will increase engine load a bit while they're turned on.

If you have EasyDIS there's a MAF diagnostic test. It will tell you idle voltage specs for your car and measure the MAF voltage. It's quite vague numbers though. For my car it's 0.66V and to somewhere above 1V window.
 

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5v.

Low voltage is most likely low SUPPLY voltage. It usually means either the maf itself is shorting
the power supply, or there's a pinched or open wire somewhere.

www.newtis.info for wiring diagrams.

t
thinking about it differently
 

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MAF signal voltage range is 0V - 5V. The higher the air mass the higher the voltage. So it definitely won't be 5V at idle. It will be somewhere above 4V at full load but even at full load it won't reach full 5V.
 

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Nah, I was saying that the error he's getting is because the SUPPLY voltage is low, not the SIGNAL voltage is low.

Since the signal voltage can go to almost 0, as you point out, it's never going to be checked for 'low'- it might give
a 'plausibility' error, if it's reading low and engine revs are high with an open throttle, but not a 'low voltage' error.

t
 

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2003 330cic, 2003 325iT
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What is the correct maf sensor signal wire voltage at idle?
2001 330ci manual m54 turboed

Getting a maf code p0102 maf sensor low circuit voltage
Only code coming up
New maf sensor
Throttle doesn’t do anything
What brand sensor?
 

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E30M3 Race F10 535 R1150Rt M Coupe
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1,465 Posts
Although I don't have any values, instrument cluster test #4 is a terrific performance indicator. Some very smart guys on the M5 board figured this out some time ago and have a posting area for values. Maybe (if not already?) someone should start one.

On the S62 there's an issue that there is NO test plan for: Car runs fair, and down on power. After exhausting all possibilities the best thing is to go to the test (# 4.1) and do a long hard run in 4th or 5th gear and see what the highest attainable instant flow rate (that's a calculated number of injector flow) of the injectors. If it's below XX.X value, replace all 4 cam sensors (factory only) and two new AMM slip in units.

Bam, 50 HP gained back! (naturally it will be different for a motor half the size of the S62.)

It's a great test and doesn't lie. Lets say you do headers, cams etc. If you have the proper tune the flow rate will be higher. It's like a dyno right in the cluster/DME.
For the S62 the highest recorded number is 140 LPH. Best I ever got was 136.
Again I have no baseline for all the variants of the M54 engine. Given enough time and dutiful input on behalf of the members, some VERY useful data could be collected.

TEST 04. - Momentary Consumption
Sub-Tests:
0267 4.0 = 26.7 liters/1000km
0073 4.1 = 7.3 liters per hour
 
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