I have the same prob with my 1.9td .I have changed my oil recently and have even changed my oil pump thinking that van doing nearly 200k thouught might need replacing .However the light still flashes and the other day started beeping .So next on my list is to change both oil pressure switches .On is on the head and the other is by the oil filter.Hope this helps you mate .T:

 

are you losing your rev counter when it comes on?

 

Thanks for the replys folks are the oil sensors a big job and any ideas as to where i can buy them to, in regards to sammymelia post i dont think im losing revs but couldnt say 100% as ive just keeping an eye on the red light!!!! if it is losing revs what do you think this could indicate??? thanks again both.

 

more likely to be a DOP fault than a sensor - search is your friend T:

 

there is a wire from the alternator which is for the rev counter and the oil light, check if your rev counter goes off when the oil light comes on. mine sthe blue light dash by the way. if it does id say u have a broken wire / faulty connection. as for the oil pressurte switch its an easy job get them from vw or ebay or motor factors. there is inly a single wire into the switch

 

I havent got a rev counter so thats ruled that out on mine lolT:

 

No it doesn't - engine RPM is still used by the DOP system

 

From an earlier post:

VAG vehicles have been using DOP (dynamic oil pressure) since the 80's, this means that two oil pressure switches and engine RPM is used to determine oil pressure rather than the system of a single switch. Low oil pressure problems are typical of high-mileage VAG cars with worn bearings and oil that is hot (and thin). The combination of thin oil and worn main bearings means that the oil pressure is marginal at lower RPM where the oil pump is not spinning as fast as it does when driving - hence the DOP system...

To check your sensors and hence oil pressure:


The first one to do is the one on the side of the cylinder head. This is a conventional low-pressure sensor. It is normally closed and opens at (I think) 0.3 bar on a tdi.

The van instrument cluster always 'monitors' this sensor, and when it switches the low pressure light comes on. This is the sensor that switches on the low oil pressure light when you turn the key before starting. This sensor is not connected to the oil pressure warning buzzer. It is connected to the wiring harness with a blue/black wire. To check this sensor, turn the ignition on; the oil pressure warning light should come on (flash) thanks to the low pressure sender on the cyl. head. If the light doesn’t come on there’s a problem with the low pressure sender, the wiring to that sender, or the dash cluster. A test light between the sensor and the positive battery post should light when the van is off and go out when the van is idling, if the sensor (and oil pressure) is ok.

The second sensor is normally open and closes at a fairly high pressure depending on engine type (1.4 bar for normally aspirated diesels and some TDs, and 1.9 bar for MK3 tdi (again - I think)).

The instrument cluster only monitors this sensor when the engine is over 1800 - 2000RPM and if this sensor is not switched by 1800-2000 RPM the oil buzzer will sound and the oil pressure light will also flash. It’s typically white, grey, or black in colour and is connected to the wiring harness with a yellow wire. To test this sensor, Disconnect the wire to the high pressure sensor on the filter flange and let it float. The oil buzzer should now come on when the van is above 2000 RPM. Now ground the yellow wire and rev the engine past 2000 RPM… the buzzer should not sound at all. If you fail either of these tests you have sensor issues, wiring, alternator wiring, or instrument cluster issues. A test light between the sensor and the positive battery terminal should be 'off' at warm idle and come 'on' as you rev to 1800-2k RPM, if the sensor on the flange is working properly. If the buzzer still sounds with the wire to the sensor grounded the problem is most likely the wiring to the instrument cluster.

To summarise, (assuming your wiring is all ok) then:


* A flashing oil light, on its own is the function of the low pressure sensor on the cyl. head or a lack of RPM signal from the alternator


* A flashing oil light and buzzer are both a function of the high-pressure sensor on the filter flange.


* The high pressure sensor is only monitored when the engine is running at or over 1800-2000 RPM.

Hope this helps in sorting your problem.

 

From an earlier post:




Hope this helps in sorting your problem.

Is this the same for the T4 1.9 diesel?

 

ok will check rev counter if the light happens again thanks for the sensor info will look into it. im new to this Penbryn so could you please educate me on what a DOP fault is??

 

thanks penbryn for youre speedy reply, so assuming the problem is one of the above mentioned does it need to be sorted straight away and could it cause any lasting damage to the engine?? Also would it be ok to rule out a head gasket problem!

 

Could somebody please answer Gazza2011.

I have expactly the same problem, and I do not want to start changing oil, pumps, or sensors if they are not normally the problems.....

Please help, I am worried about using my van in case I cause more problems.

HELP>>>>>>>

 

a big please bump

 

Could somebody please answer Gazza2011.

They already have...
Try reading post #9 - it has all the information that you need to fault-find your problem

 

an absolute big up to pembryn who really seems to know what he is talking about followed his guides and sorted my prob right out .rev counter not working oil light flashing turned out to be the can bus wires were they plug into fuse box 1 pin had the slightest corrosion on it cleaned all good cheers guys

 

I have a 2003 T4 with the 2.4 TDI engine - does this have the same wiring for the oil pressure warning system? Hads load of grief with the van so far as the week after I bought it (95k on the clock) and put new breaks all round (and a full service) the water pump failed and blew a hole in the cam belt cover and ripped the teeth off the belt -yes you guessed it, recon engine time.
Then discovered on long journeys (20mins plus) that the oil pressure warning light and alarm sounds when I come off high revs (slowing down coming off the motorway etc) .
I've replaced the oil filter, oil and oil pressure switch but this made no difference - so I'm thinking (I'm no mechanic) electrical fault or the actual sensor itself? The oil pressure has been tested and is actually fine but the noise and flashing light is driving me insane!
Can anyone tell me where the sensor is? and is it easy to get to?
I should add that the airbag light is permenantly on on the dash but VW have said its working ok and just a fault on the dash???
Someone told me at VW that I may need to replace the whole dash (as its not a simple circuit board swap) to solve the problem of the oil pressure warning light/alarm if its electrical???? gotta be kiddin!
any advice would be really welcome?
cheers dave:ILU:

 

I have a 2003 T4 with the 2.4 TDI engine - does this have the same wiring for the oil pressure warning system? Hads load of grief with the van so far as the week after I bought it (95k on the clock) and put new breaks all round (and a full service) the water pump failed and blew a hole in the cam belt cover and ripped the teeth off the belt -yes you guessed it, recon engine time.
Then discovered on long journeys (20mins plus) that the oil pressure warning light and alarm sounds when I come off high revs (slowing down coming off the motorway etc) .
I've replaced the oil filter, oil and oil pressure switch but this made no difference - so I'm thinking (I'm no mechanic) electrical fault or the actual sensor itself? The oil pressure has been tested and is actually fine but the noise and flashing light is driving me insane!
Can anyone tell me where the sensor is? and is it easy to get to?
I should add that the airbag light is permenantly on on the dash but VW have said its working ok and just a fault on the dash???
Someone told me at VW that I may need to replace the whole dash (as its not a simple circuit board swap) to solve the problem of the oil pressure warning light/alarm if its electrical???? gotta be kiddin!
any advice would be really welcome?
cheers dave:ILU:

 

1996 N reg 1.9 Diesel SWB

I can only see the high pressure sensor by the oil filter. I cannot see the low pressure one on the head despite getting right in there with a torch.

Also, the wire going to the high oil pressure sensor is blue and black. The wiring diagram I have found says it should be yellow. There is a yellow one in the same connector block which is cut off.

Please can anyone tell me if there is one or two sensors on this vehicle and what colour is the wire going to the high pressure sensor ?

Thanks
Steve