Oil Level Sensor Bench Test

Little Dog

Little Dog

A2OC Donor
European-Union
Can anybody advise a test procedure for an oil level sensor that is off the car?

IMG_1359[1].JPG


Plugging it in and using VCDS is not an option so I was looking for an indicative test using a multimeter. Something like this:


Thank you.
 
I managed to fix one by spraying electrical contact spray into the tiny hole at the bottom, that was 6 months ago and its still fine.
Mind you , it might have just been a bad contact on the plug
 
If it's the same as in the FSI, and I'm sure it is, then it's a three wire sensor.
Pin 1 = 12 V
Pin 2 = 0 V
Pin 3 = Output to Instrument Cluster. Probably DC, varying with oil level. It's described as level and temperature sensor, but I don't think it is, just level.
Mac.
Edit: The output may be PWM, but a meter would see it as varying DC, I think.
 
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Thank you for your responses all, I think this is one I'm going to have to pass on. I've never had any issues with oil level or temperature, I'm building a replacement engine and all sensors, with the exception of cam sensor. have survived 170k miles and could be a little tired. They are inexpensive so I have been buying new. The oil level and temperature sensor is quite expensive so I thought I would test it (I've found other items that have failed without giving trouble).
I thought testing would involve connecting an ohmmeter putting some oil in a jug with the sensor in it and observing the change in resistance. Warm the oil and the resistance on second pin will change. Not so, this is a digital not analogue sensor. The post by @CrispyEdd raised my suspicions that this was not going to be easy.
Pin 1 = 12 V
Pin 2 = 0 V
Pin 3 = Output to Instrument Cluster. Probably DC
Something in there has got a power supply and there is just one output. So if this is a combined level / temperature sensor then the output can't be analogue.
I then watched the video posted by @robskiA2tdi , the pressentor ruins his experiment by throwing hot tea at his sensore (he had already decided to replace the sensor) and we don't know if the oil level functionality on his sensor is working. Temperature definitely is working.
Using an inexpensive oscilloscope he establishes that the output is a digital signal that the ECU can interpret:

Oil 1.jpg


There are two spacings of pulses suggesting two digital signals.

The signal changes in hot tea, however I can't see a pattern there so I can't interpret it.

Oil 2.jpg


An oscilloscope is only £30 but on this occasion I'm going to fit the old sensor without a test. If I get oil level warnings or spuriouse oil temperature readings the it is an easy replace.
:
 
From my experience (BHC engine) with this type of oil level/temperature sensor - this thing usually does not fail totally, but start to get "stuck" at some point. You start to get random "Low oil level" faults, and while monitoring output value in VCDS - sometimes you see a "strange" value there. Diagnosis on the table might not be very true.

On the bright side - I bought a cheap replacement (about 20 euro) - and it works flawlessly (tested it during oil change - output seems to be ok) - no faults etc.
 
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