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What's the correct voltage readings on a MAF sensor?
#1
Most MAF info I find online tells me that the range on the signal wire is 0 volts up to 5v, with .8-1.5v at idle.

I'm getting 2.6v at idle and 4.1v at WOT (wide open throttle).
If this range is wrong, this could account for the engine's lack of power, especially at higher RPM's.
And, I'd suppose, poor gas mileage at lower RPM's.

During this voltage test, I noticed that at 70-80% of WOT the reading was already at 4volts - and stayed stuck at 4v as I increased all the way to WOT.

In case it helps anyone out there, these are the pinouts I discovered.  The pins are labeled with numbers inside the female part of the plug (on the MAF itself):

Counting from the left:


1 beige - ??

2 white - 14.30v idle to 14.50v Max

3 green - ground (either overall ground or sensor ground)

5 yellow - 2.6v idle to 4v 80% and 4v max

6 purple - ground (I'd guess this ground is the sensor ground)



Now, as far as what the actual voltage range is supposed to be (1.9d DW8 WJY MKII) - the google is not giving me any info on that.

[UPDATE]: I've got the Haynes manual now, and the "M59" data manual from Citroen: I have not found any data regarding this MAF sensor.
[Image: 177657.png]   2004 1.9D DW8 WJY with black spray paint on wheels instead of flimsy plastic wheel covers.
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#2
[UPDATE]: I've got the Haynes manual now (thanks!), and the "M59" data manual from Citroen:
I have not found any data regarding this MAF sensor and the right voltages it should be sending out.

I've driven with the MAF sensor disconnected, and no change. This might indicate that the sensor is fine.
Maybe the Throttle Position Sensor (TPS)?

Or, could it be the ECU software problem, here:
http://www.berlingoforum.co.uk/thread-11530.html
[Image: 177657.png]   2004 1.9D DW8 WJY with black spray paint on wheels instead of flimsy plastic wheel covers.
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#3
Little update: I installed a new MAF sensor and haven't had a chance to test the voltage readings yet. But the car does not feel like it's running any better.

[UPDATE: Voltage reading on the new 3rd party MAF sensor for Berlingo is the same as on the old Audi MAF sensor: 2.6v at idle and 4.1v at open throttle. I'm perplexed].


Turns out the old MAF sensor was for Audi not Berlingo.

When I first experienced the loss of power I had just prior:

Installed one of the EGR vacuum tubes that had been missing.

Improperly sprayed electric contact cleaner on the MAF sensor (while on the car) and then started up the motor without much dry time. My bad. There was an explosive sound which I thought was from aerosol fumes in the air intake. But maybe a false assumption.

Later I disconnected that vacuum line, found another EGR vacuum like an reconnected them both, with and without the EGR blanking plate after the concertina elbow; all testing to see what would bring the power back.

I got a voltmeter on the MAF sensor with a reading of 2.6v at idle and 4.1v at open throttle. I thought the range should have been 1v up to 4.5 or 5v so I bought a new sensor.

Like I said then the parts store guy and I noticed the old MAF is marked Audi.

Still, there's no improvement in power. I don't know what happened but I'd like to get it sorted.

While installing the electric plug on the new MAF sensor the little tab broke. So now the harness doesn't "click" shut, so I hold it closed with a zip plastic tie.

EGR is blanked now but it seemed stuck open (clean air) prior to blanking and reconnecting vacuums.

Another reason the MAF cleaning was improper: the contact cleaner contained a solvent and a lubricant. Surprise! I didn't expect either to appear in an electrical contact cleaner. I already knew that solvents such as carb cleaner/brake cleaner are not good for MAF sensors., despite people writing on the web that they use those anyway.

But if replacing my poorly cleaned MAF sensor did not solve the problem, then I'm stuck for ideas.




Sent from i myPhone using Tapatalk
[Image: 177657.png]   2004 1.9D DW8 WJY with black spray paint on wheels instead of flimsy plastic wheel covers.
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#4
Currently I'm waiting for an answer from the shop about returning that brand-new MAF sensor (chinese) which achieved no improvement whatsoever over my old MAF sensor.

Meanwhile a guy with a Y&Y OMD-II code reader helped me diagnose. Yes there was a code for the MAF sensor, but also the engine heat sensor. But that might have been triggered because the heat sensor was disconnected for a driving test (engine performed worse).

In the process, the guy began to look around the throttle wire and noticed that the pedal was not pulling the wire thru its full range. The culprit: broken clips on the throttle wire have disappeared. Temporary fix with a plastic "zip" pull to serve as a clamp/clip.

So for some strange reason, this clip happened to perish at exactly the same time I had replaced the air box, reconnected some vacuum lines, and cleaned the MAF sensor. None of those was the cause of this low acceleration issue. It was the missing clip.

Teaches me that when I've examined all possibilities and eliminated all of them, the cause could be found in another possibility which was not yet considered.
[Image: 177657.png]   2004 1.9D DW8 WJY with black spray paint on wheels instead of flimsy plastic wheel covers.
[+] 1 user says Thank You to teddyc1 for this post
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