Red oil can flashing

[Jeff TT]

Ok newbie here in need of some advise,  so my 2009 Q5 with the 3.0 dti engine  ( 72k miles ) has been faultless for the past 2 years and enjoyed it.

However a week or so ago whilst on the motorway the ancillary belt frayed and it whipped around and damaged the loom at the front of the sump and broke the connector off the oil pressure sender. This was my first warning something was up as the dash lit up with red oil can and  beeping to check oil level,  I pulled over and saw the ancillary belt so called recovery and got it home.
 

So pulled the front in to service position and changed the water pump, ancillary belt and pulleys, the tensioner was in great condition and so did not do that, all part were from Audi.  The cable loom was only slightly damaged not cut just a few places where the insulation was gone, I made complete and careful repairs, the oil pressure switch plastic was broken so replaced it with one from Audi.  The connector to the sensor however was also damaged but could not get one so refitted it and cable tied it in place, all looked good, new antifreeze and started up fine, no issues.

Well that was short lived as soon as I got pulled out onto the main road three beeps and red oil can and message saying check oil !!    surfice to say the level was checked in the MMI display and was showing full ??   I have checked and double checked everything and can not find any issue elsewhere, I even changed the oil pressure sender again, the car runs fine and sounds fine but that red can flashing is worrying.

After days of messing about I finally gave up and sent it to Audi, they had it 6 hours and concluded the connection on the oil pressure sender was the issue, but would need to order one and on back order, quoted me 150 Euro to change it and the sensor again !!

Frustrated returned home, an 80 mile round trip at motorway speeds with  NO issues.

In desperation I cut the plug off and soldered the cables directly to the sensor so no chance of a bad connection now, all back together exactly the same issue, starts up fine no warning will tick over for as long as you want with no warning, but drive out of my road and beep beep beep ...  argh !!!

So today I did an oil and filter change just to make me feel better about the oil level,  and yep you guessed it exactly the same issue. I can only assume this is an electrical issue as prior to the belt letting go there was no issues, and  despite my reservations I cannot believe I have low oil pressure as a result of the belt going, and still using  the car at motorway speeds sure the engine would have let go by now.

One other thing I have tried running the car with the oil pressure sender disconnected and get the same result, no warning until I drive away, guessing  a certain rev or speed level has to be attained.

So of course these things always happen at the wrong time, I have a 700 mile journey tomorrow night from the Algarve to Bilbao, will have my backside in my hand the whole way at this rate.  

 

Again what is everyone`s opinion on me actually having low or no oil pressure as a result if the belt letting go, seems not possible.

Finally any idea`s ??    is there a reset of the pressure sensor circuit needed ???

Help guys  have tomorrow to try and sort it 

Jeff

Edited April 25, 2017 by Jeff TT
spelling

[Dan3222]

Does anybody know where the oil pump is on this engine, 3.0 V6 I'm guessing?  If it's belt driven then this could be the cause potentially needing new pump maybe. But if pump is gear driven then I doubt it will be an issue.

have you had codes reset?

[Jeff TT]

I understand the oil pump is gear driven off the crank,  checked and there is no codes, comes back as all clear ??

Jeff

[Dan3222]

If it's gear driven then I would have thought that if it was not working you would have a constant low oil pressure light. Surely this is a faulty pressure sensor.

i feel for you on this one as you have a big trip ahead. I think I would be hiring a car for it!?!  At the very least I would put a ZX1 oil treatment into the engine. There are loads on the market but I rate this one highly. At least you are then trying to help avoid any engine wear but still a big risk to take.

just re-read your OP. You disconnected the sensor and it behaved exactly the same. That to me really does indicate that the sensor is at fault. Change that and go from there. They are a common fault on VAG engines!!

 

[Jeff TT]

Small update for those interested,  I completed  the journey and some more, around 1600 miles now with no engine issues and great miles per gallon so the actual oil pressure is just fine, today passed its Mot with flying colours. Still the red oil can flashes ??   Audi had the car and could not determine the fault other than to say they think it is electrical ??  anyhow looking for a wiring diagram to see if I can trace it out, vagcom reports it as oil pressure circuit malfunction so must be a wiring fault ?

Was hoping to solve the issue before I leave the UK again on the 700 + mile return trip but looking less likely,  so if anyone has a link to the wring diagram would appreciate it.

Jeff

[Dan3222]

Well great news that the trip went well. I bet there  were a few monents when your heart was in your mouth though.

i don't have a wiring diagram unfortunately but hopefully someone will have one for you.