08 passat Oil pressure low engine off warning.

JonnyM

Got this message last night no warning light on before hand.
Car ticks over but won't fire up. Mechanic thinks it could be the fuel pump???

Is the oil pressure linked to the fuel pump??

Anyone know about this warning that comes up.

biko

Diesel or petrol?

9935452

JonnyM wrote: »

Got this message last night no warning light on before hand.
Car ticks over but won't fire up. Mechanic thinks it could be the fuel pump???

Is the oil pressure linked to the fuel pump??

Anyone know about this warning that comes up.

I reckon the car is in limp home mode. Whenever the fathers car went into limp home mode the revs would cut to tickover and she wouldnt rev up but ticked over perfectly
Read the faults even if no lights are on . Fix the problem , reset the fault

jimgoose

Could there be a problem with oil pressure?

JonnyM

biko wrote: »

Diesel or petrol?

Diesel.

JonnyM

Was just talking to mechanic and he said it's the fuel pump that's gone. Says it will cost approx €380 including labour.

He's using authentic VW part. I priced part in motor factors for €180 so I might just put spurious pump back in.

JonnyM

jimgoose wrote: »

Could there be a problem with oil pressure?

Not sure I read somewhere that oil pressure switch could be wired through fuel pump in some cars not sure if it's the same for VW.

jimgoose

JonnyM wrote: »

Not sure I read somewhere that oil pressure switch could be wired through fuel pump in some cars not sure if it's the same for VW.

That sounds a bit "irregular". Do you know if the mechanic investigated the oil pressure situation? IIRC there was talk of a manufacturing problem with TDI oil pumps back around 2006 or so.

Special Circumstances

jimgoose wrote: »

That sounds a bit "irregular". Do you know if the mechanic investigated the oil pressure situation? IIRC there was talk of a manufacturing problem with TDI oil pumps back around 2006 or so.

On any other car, yes, it would seem odd to have an issue with the fuel pump trigger a low oil pressure warning but in vw land a dodgy brake bulb can cripple your car. Who knows what's wired via what?;-)

JonnyM

jimgoose wrote: »

That sounds a bit "irregular". Do you know if the mechanic investigated the oil pressure situation? IIRC there was talk of a manufacturing problem with TDI oil pumps back around 2006 or so.

No don't know if he has investigated or not but will be sure to ask.

John T Carroll

JonnyM wrote: »

Got this message last night no warning light on before hand.
Car ticks over but won't fire up. Mechanic thinks it could be the fuel pump???

Is the oil pressure linked to the fuel pump??

Anyone know about this warning that comes up.

Are you saying that the engine will run (tick over) but will not rev up?.

Re oil pressure ( could be oil pressure switch problem, if not fuel pump)
Normally, the oil pressure "warning system" isnt armed until the engine revs are at 2000 RPM, if you disconnected the wiring harness on the pressure switch, no alarm will annunciate until you rev to 2000 RPM (at least thats how it works on my petrol Bora&Polo models). Another function test that is carried out when the ignition switch is turned on, it looks to see if the pressure switch is closed (faulty), if so I think it should give maybe a continuous constant or flashing low oil pressure warning light. It may just be worth thinking about that, or just pulling off the wiring harness from the pressure switch and then see if you can rev up to 2000 RPM, at which time the alarm might or might not annunciate. You could then try a substitute or new pressure switch, but only run the engine for a short period in case of genuine oil pressure problem.

Edit: Had a good luck there and I cant find any link from fuel pump pressure to lub oil warning system, this doesnt mean of course that it doesnt exist but would be illogical. I would be very worried about running the engine even at idling speed IF there is no/low lub oil pressure. A diagnostic test may show up something.
Re the Alarm. It states in one of the links that I found...3 warning buzzers + pictogram "STOP Oil Pressure Engine OFF" which I would interpret as stop the car and switch off the engine as you have no (or low) lub oil pressure. I think the oil pressure switch setting is 0.6 Bar.

JonnyM

John T Carroll wrote: »

Are you saying that the engine will run (tick over) but will not rev up?.

Re oil pressure ( could be oil pressure switch problem, if not fuel pump)
Normally, the oil pressure "warning system" isnt armed until the engine revs are at 2000 RPM, if you disconnected the wiring harness on the pressure switch, no alarm will annunciate until you rev to 2000 RPM (at least thats how it works on my petrol Bora&Polo models). Another function test that is carried out when the ignition switch is turned on, it looks to see if the pressure switch is closed (faulty), if so I think it should give maybe a continuous constant or flashing low oil pressure warning light. It may just be worth thinking about that, or just pulling off the wiring harness from the pressure switch and then see if you can rev up to 2000 RPM, at which time the alarm might or might not annunciate. You could then try a substitute or new pressure switch, but only run the engine for a short period in case of genuine oil pressure problem.

Edit: Had a good luck there and I cant find any link from fuel pump pressure to lub oil warning system, this doesnt mean of course that it doesnt exist but would be illogical. I would be very worried about running the engine even at idling speed IF there is no/low lub oil pressure. A diagnostic test may show up something.
Re the Alarm. It states in one of the links that I found...3 warning buzzers + pictogram "STOP Oil Pressure Engine OFF" which I would interpret as stop the car and switch off the engine as you have no (or low) lub oil pressure. I think the oil pressure switch setting is 0.6 Bar.

Engine will not start at all.

John T Carroll

JonnyM wrote: »

Engine will not start at all.

That's good news in one sense, I did read somewhere a long ago that even though the lub oil alarm is not normally armed until 2000 RPM that it can also annunciate if the revs drop below the normal idling RPM so hopefully that's what happened in your case and the fuel pump is your problem, best of luck.

JonnyM

Changed fuel pump. All sorted. Thanks for your input.

John T Carroll

JonnyM wrote: »

Changed fuel pump. All sorted. Thanks for your input.

Delighted your sorted and great to get feedback. John