Engine pressure warning. confused.

[georgeg1]

Hi guys,
today my 'Engine Pressure Warning' light came on.
I know this requires immediate attention but, it's only intermittent.
It's switches off as usual when the engine is started, but then it comes on around 10 mins into driving. It lasts on average about 30secs solid then goes out again for random amounts of time.
I cant see any link with my current speed or gear that affects it.
i'm half thinking it's something to do with the battery connection as my sunroof cut out the other day and i was told by my mechanic that there wasn't enough power coming from the battery due to a loose connection.
that could be completely unrelated, but i thought i'd include it.
does anyone have any ideas?
engine sounds fine, no knocking or hissing, oil level is fine as that's the first thing i checked.

possibly need to change the oil filter?
i'm clueless.
any help would be wicked. cheers

Audi 80 tdi 1992

[zollaf]

there are 2 pressure sensors. low rpm one that switches the warning light off when you start the engine. this one is normally earthed until the oil pressure opens the circuit. the other is activated around 2000 rpm. this one is normally open and requires the switch to earth to stop the warning , and also makes a buzzing sound. my 80 runs a 16v oil filter housing so i could fit the pressure gauge from my old coupe, so i dont run the 2000 rpm sensor. i just connected the end of the wire that normally plugs into the sensor straight to earth. i think its this sensor on yours thats playing up. look on the filter housing and you should see both sensors. i cant remember which is which but trail and error should work for you.

[helmsy157]

Hi there, had this with one of mine, and after all the above, gave the cooling system a good clean which gave some improvement but then fitted a new radiator and problem gone, these are cheap from Germany