Oil Sensor Defective

[Borg55]

I’ve got a yellow “oil sensor defective” light on my Audi A3 2006. This is a new sensor, the fuse is good, the wires are good. The bonnet switch is working. What could it possibly be? Driving me nuts

thanks in advance

[cliffcoggin]

New or not, it can still be defective, especially if it is a cheap after market sensor. If you paid for it to be done I suggest you take the car back to him. On the other hand there may be something else involved. Why did you change it in the first place? Are there any other symptoms?

[Borg55]

Hi Cliff, 

thanks for getting back to me, work was done by myself, it was indeed an aftermarket sensor, but this would be the third to fail in a very short time and it wasn’t exactly cheap, so I am hesitant to buy another one if the problem lies elsewhere. It was changed due to the oil sensor defective light coming on. No other symptoms. Fuses are fine, is there a relay I have missed somewhere? Thanks again, will

[Magnet]

Hello Borg,

Thanks for the additional information. 

As Cliff says, unfortunately, new may not equate to serviceable, despite the odds against a couple of them ( from the same supplier’s batch?) being defective. 

Couple of points here Borg:- Are we talking oil level sensor, or oil pressure sensor here?

                                                 Make of the sensor/s and where you bought it/them?

‘.....not cheap...’. Have you compared the price paid with buying a genuine VAG - hopefully with a little discount? 

‘ Fuse is fine...’. Have you removed the fuse, sprayed some contact cleaner, refitted and waggled the fuse to ensure you don’t have any contact resistance there? Contact on to sensor nice and clean/ cleaned and wiring check for any damage? 

From the book of simple things first - make sure the fuse and connections have been cleaned with contact cleaner. 

You don’t tell us whether the warning light goes out when you change the sensor, then comes back on, or if it doesn’t go out at all. 

Simple question, to which I don’t know the answer in your case, but does the fault code need to removed as part of this job before the light will extinguish? Again, worth checking - it could be as simple as that. 

Anyone on here with any direct experience of this? 

Perhaps you could let us know how you get on.

Kind regards,

Gareth. 

Perhaps 

 

             

[cliffcoggin]

Three failures in succession suggests to me that the cause lies elsewhere, unless they were unfit for purpose. To add to Gareth's ideas I would also check all the wiring between sensor and loom, particularly the connectors. Look for cracked or damaged insulation, dirty or corroded contacts, loose plug connections etc.