Red Oil pressure warning light

[jackyaudi]

OK so today I started the car, and after a bit of driving I got that deadly red oil pressure flashing light. I stopped the car right away, checked the oil level: fine. Engine sounds fine, and healthy. No leaks near the oil pan, and when I open the oil cap I see some oil circulating around (although thats not an indicator).

Not sure what to do next. It could be a faulty sensor, the oil pump defective, oil screen, or the pressure relief valve. Problem is, I cannot tell which.

Had the car for 4 years now, oil changes every 4500 miles, use only big oil filter from Audi, and synthetic 5W40 of course. Did a seafoam once or twice in the past 2 years.

What do you guys recommend to do?

[Valve_Cover]

I call sludge :P

Easy step if you have a place to lift the car would be to take off the oil pan and have a looksy, if not then plug an oil pressure guage in and check oil pressure while driving. That's where I'd start

[jackyaudi]

Well, car is very well maintained: Auto-rx done last year, seafoam, oil change every 5000KM, new oil filter each time, Lubro Molly anti-friction for the engine, etc etc

Also, when last year I had a problem with the oil level sensor, when we were changing it, I looked inside the oil pan with a light and things looked extremely clean in there, you could see many parts through that oil sensor hole. I also see oil circulating at the valve cover when I open the oil cap, and I dont hear any loud noises or any unusual noises.

So I am trying to rule out for now simple things like electric stuff, pressure relief valve, oil pressure, and so on, before I go and change the pick up tube/screen.

1) Anyone knows how to check if the pressure relief valve has gone bad?

2) Also, whats the best way to check the oil pressure on these cars?

Thanks all.

[jackyaudi]

Bump for Tuesday morning with the red light of death :)

Ironically, all this is happening while I noticed something weird. The night before all this happened, my KM left-to-the-tank was at 450KM (full tank). I noticed when I started the car that it was suddenly 600KM, where no fuel was added of course, and 3 minutes later I get the low pressure light flashing. Could all this be related to some electrical problem/ECU? How can I rule all this out?

[Bische]

Check for codes?

[jackyaudi]

Not yet.. VAGCOM is at my friend's place, and I dont wanna drive there, we will probably just tow it there directly, but am trying to see the easiest way to check oil pressure and to also check on that oil pressure sensor. Right now am trying to locate exactly where the oil pressure switch is on a picture, coz I think that where I should be plugging the oil pressure gauge to...

[walky_talky20]

Here's a post I made a while back about checking the oil pressure on 2001+ 1.8T's:

The easiest way to go about it is to pay someone to do it, lol. But you do it using a mechanical oil pressure gauge. Your mechanic probably has one, but he may have to dig it out. It isn't a tool he uses everyday. They usually are housed in a little red case (they are almost always red, who knows why), and they look like this when you open them:



Then you hook it up to the oil pressure check port. It is an unused plug on the top of the oil filter flange/housing. Here is a photo for reference (2001+ engine shown, earlier engines are similar):



The little red plug is the aux check port. The alternative hookup is to remove the factory oil pressure switch and connect the gauge there. That is the item in the red box. Both connections use a Metric 10x1.0 thread, so you use the appropriate adapter on your gauge for that. It should take a mechanic no more than 15 minutes or so to get a reading, that's after he finds his gauge. Perhaps another 15 minutes to put the car back together. You want hot (~200F) and cold readings, ideally. As stated above, the hot reading is more important as that is when the pressure is at its lowest.

The top Auxiliary check port is pretty easy to see in between the intake manifold runners with a flashlight. I go over how to get at it in my Oil Pressure Sender Install Write-up:
http://www.audizine.com/forum/showth...stall-Write-Up

[jackyaudi]

walky_talky20: you are awesome, that pic is very straightforward. I will try whichever is easier to measure the oil pressure. I gotta go get that oil pressure gauge from somewhere now.

Thanks a lot!

Any way of testing the oil pressure sensor, and where is it exactly, I dont think its on the above pic is it?

[walky_talky20]

Yep, the item in the red box is the oil pressure switch. Best way to test it is to check your oil pressure. If the pressure meets spec, then the switch must be bad. Normal oil pressure is way above what would ever trip the switch, so you shouldn't have any issue figuring out what the problem is for sure.

[jackyaudi]

Yep, the item in the red box is the oil pressure switch. Best way to test it is to check your oil pressure. If the pressure meets spec, then the switch must be bad. Normal oil pressure is way above what would ever trip the switch, so you shouldn't have any issue figuring out what the problem is for sure.

wow, why they call it "oil pressure switch", it looks like a normal bolt or screw... Ya the oil pressure check will rule everything at this point..

[walky_talky20]

There is a 1-wire electrical connector on the rear. With pressure, the electrical ground is applied to the wire. Without pressure, it is open-circuit. Switchover is anywhere between 16 and 23 psi or so (there is some variance in the production of the switches).

And looks like harbor freight has a kit for $20:
http://www.harborfreight.com/engine-...kit-98949.html

It appears that it does include the necessary M10x1.0 adapter.

[jackyaudi]

There is a 1-wire electrical connector on the rear. With pressure, the electrical ground is applied to the wire. Without pressure, it is open-circuit. Switchover is anywhere between 16 and 23 psi or so (there is some variance in the production of the switches).

And looks like harbor freight has a kit for $20:
http://www.harborfreight.com/engine-...kit-98949.html

It appears that it does include the necessary M10x1.0 adapter.

OK, so that 1-wire electrical connector, its on the rear of the assembly on the pic above am guessing? I could probably check the wire there maybe if its loose or bad it would trigger the red light? Doubt it, but worth checking. Do you have any pics of where that wire is, I will also try to located it when I go under the hood later.

[Audi Skate Snow]

There is a 1-wire electrical connector on the rear. With pressure, the electrical ground is applied to the wire. Without pressure, it is open-circuit. Switchover is anywhere between 16 and 23 psi or so (there is some variance in the production of the switches).

And looks like harbor freight has a kit for $20:
http://www.harborfreight.com/engine-...kit-98949.html

It appears that it does include the necessary M10x1.0 adapter.

gotta love harbor freight. Well, love them if it doesn't brake in five minutes.

[jackyaudi]

Alright, am posting this for future reference for others.

Looks like the pressure sensor is the one which the red arrow points to, its the only sensor in that area which has only 1 wire as walky_talky20 mentioned:




Then that wire goes into arrow #1 on the red arrow, which then by itself goes into arrow #2, and all of that goes Directly into the ECU box. I checked the wire, it seems fine and attached, so the only other possibility is that the sensor in itself is defective, and its about $26 at the dealer, if thats the issue. Will check oil pressure first, and then go from there.




If you would like to make any changes or the info is not correct, please let me know so I fix it up.

[walky_talky20]

Yep, that is the oil pressure switch. You can take it off and connect your gauge at that location, or you can remove the plug on the top of the housing and connect there (like I did in my write-up). Either way will give you the same reading.

Chances of an actual oil pressure problem vs. a bad pressure switch are probably 10 to 1. Oil sludge is very common on the 1.8T engine and clogging of the pickup screen is the main failure. But the pressure switches do fail once in a while, so there is hope. If it is sludge-related, you may be able to take advantage of some help from Audi of America's sludge settlement. They have a 10 year, 120,000 sludge warranty extension to cover this stuff. 100% coverage with oil change documents. 50% coverage without. Perhaps something to look into if need be.

[jackyaudi]

Knowing from my experience with the Audi dealers here, I wont even bother with them. I mean when I was UNDER warranty, I would struggle with them and its hell everytime I go there or call Audi Canada. Just not worth the high blood pressure and anger. And my car is modified a lot, so they would probably wont like that either.

Lastly: I decided that if I have low pressure readings, to actually change not just the pickup tube/screen, but also the oil pump itself. It makes no sense to get that far and not change the oil pump, even if there is 50% risk that its at fault. The car is 9 years old now, so it wont be a bad idea to change it anyhow. I will probably have a garage do the job, coz my back will kill me for 2 weeks if I attempt this at my friend's garage, and its a PITA to do without a lift.

[jackyaudi]

Update: the audi gods are back...

A bunch of weird things are happening (all of which happened at once, the same time as the red oil warning light)

1. Hood opens but that does not show in the cluster. All other doors/trunk warnings work though.

2. The lights on the shifter don't work anymore (P, D, R, +, -, etc). The brake pedal light still works though!

3. Sometimes (happened twice tonight), when I start the car I hear 4 beeps like when the red warning lights come (ex. coolant, oil pressure), but with absolutely no signs displayed. It even says "OK". Weird.

4. So I warm the car to normal temp, engine sounds smooth as silk. Revved to 2000 RPM, then slowly to 3000 RPM, still no Red Oil pressure warnings. Engine still sounds smooth. I dont wanna drive till friday after pressure tests. Opened the oil cap while engine is running, saw a lot of oil flowing around the plastic cover which is over the cams, and its constant flow, thick and quick flow. Turbo sounds very normal, just as new, so its definitely not starving or lacking oil.

5. I get random warnings that the Turn signals being out, but they aint, they flash fine.

So what the hell is going on? Sounds like the cluster or ECU or some electrical thing is really having a party, and this is not time coz I am trying to resolve the Red warning of death issue.

I will still do the pressure test on Friday with a friend, and we got a pressure switch from the dealer, just in case. But with all that weird stuff going on in the cluster and electronics, I have no idea what to do now. Yes I reset the battery, does not help yet. Is it ECU, cluster, fuses, some weird magic?

[diagnosticator]

The four beeps you are hearing may be the alarm horn module. The module will sound off like that when the internal battery is getting weak, and is not accepting a full charge anymore due to age. This is consistent with the IC not showing anything when you hear the beeps.

[jackyaudi]

The four beeps you are hearing may be the alarm horn module. The module will sound off like that when the internal battery is getting weak, and is not accepting a full charge anymore due to age. This is consistent with the IC not showing anything when you hear the beeps.

EDIT: thanks for your feedback. always appreciated.

[mayhem]

He means the battery for the alarm, not the large car abttery under the hood.

[jackyaudi]

^^ Ya that is what it looks like.

I am starting to think the cluster is acting up on random things here and there. Its hard to believe the lights of the gear shifter would suddenly not work, along with everything else: hood sensor, beeps, and maybe also the red oil pressure sensor.

[Bische]

Check for moisture on your control units connectors, did you pull the codes?

[jackyaudi]

Check for moisture on your control units connectors, did you pull the codes?

I will pull codes same time I do the oil pressure test. My friend has both :)

Its weird that the gear selector lights are out, but the little one for the brake pedal still works. Unless they are on different wires or something. For the hood, I will check the sensor there. I might open up the ECU in the future and take a look. I will also check all the fuses one by one.

I wonder if there exist a way to "reset" the instrument cluster.

[mark333]

I had my Red oil light come on yesterday too... I pressure tested the system and found:
Cold startup - 80psi
operating temp idle - 30psi
3500rpm operating temp - 80psi
to the floor at operating temp -110psi

....Seemed pretty normal?

I ended up changing the pressure switch with one from another car i had laying around - Light is gone.


As far as resetting your cluster, maybe try disconnecting the battery terminals and putting the two together (capacitive discharge). This is one way to reset all the monitors on the vehicle.

[jackyaudi]

I had my Red oil light come on yesterday too... I pressure tested the system and found:
Cold startup - 80psi
operating temp idle - 30psi
3500rpm operating temp - 80psi
to the floor at operating temp -110psi

....Seemed pretty normal?

I ended up changing the pressure switch with one from another car i had laying around - Light is gone.


As far as resetting your cluster, maybe try disconnecting the battery terminals and putting the two together (capacitive discharge). This is one way to reset all the monitors on the vehicle.

Thanks for sharing your input!

Yes those readings do seem normal, glad it was the pressure switch for you!! I got a spare one in case my readings are similar.
I opened this thread for all the electrical issues I am suddenly having: http://www.audizine.com/forum/showth...-weird-problem

[Mike02A4]

I have an oil pressure gauge under the hood of my car. What I did was I used the newsouth 2.0t banjoport adapter to replace the factory banjo bolt for the turbo feed. I then used a few fittings and hooked up an autometer mechanical oil pressure gauge I had. I did this out of curiosity after reading many threads on here about sludge and the red oil light. I can email a picture if you are interested. Another bonus for using the banjoport fitting is the oil feed holes are larger than the factory banjo bolt.

[jackyaudi]

^^ Sure a pic would be nice. but what did not you just put the gauge inside the car, much better that way, and you can monitor it while driving, idling, etc

[Mike02A4]

Basically, I just did it for testing purposes to see for myself what the pressure was after reading so many threads on sludge. I also didn't really want to spend any money. The banjoport adapter was $20 and the gauge and fittings I already had laying around in the garage.

Message me your email and I will send the picture tomorrow.

[jcg05c]

This same light comes on once in a blue moon. Last time was last night for like 10 seconds and then not again. The time before that was like 3 months ago. so weird

[jackyaudi]

This same light comes on once in a blue moon. Last time was last night for like 10 seconds and then not again. The time before that was like 3 months ago. so weird

Did you check the pressure though? Could be just the sensor acting up in your case. I will find out tomorrow the pressure results. If you wanna see weird, check this http://www.audizine.com/forum/showth...-weird-problem

[Bische]

I will pull codes same time I do the oil pressure test. My friend has both :)

Its weird that the gear selector lights are out, but the little one for the brake pedal still works. Unless they are on different wires or something. For the hood, I will check the sensor there. I might open up the ECU in the future and take a look. I will also check all the fuses one by one.

I wonder if there exist a way to "reset" the instrument cluster.

The ecu sits just under the front window, drivers side, in a plastic box that breaks with ease. The comfort control unit is under the carpet/seat drivers side, could be worth ruling out moisture short cricutting on the modules.

[jackyaudi]

^^ thanks, did not know that comfort control unit is there.

[jackyaudi]

F**** car.. She is used to give me false alarms all the time.

Pressure results, all at operating temps:
Idle: 24-26 pis
2000 RPM: ~54 - 56 psi
3000 RPM: ~60 - 62 psi
4000 RPM: ~65 - 67 psi
5000 RPM: ~70 - 72 psi

The old pressure switch is fine. When removed I got the error, when plugged back, it went away. Took her for an hour drive, no errors, even at 6000 RPM. So nothing done/replaced.

[rwstehr]

Thanks to all for the advice and walky_talky20 for the diagram.

I checked oil pressure cold and it was around 55 psi. As the engine warmed up, the pressure decreased. At full operating temperature, the pressure had dropped to about 16 psi.

I decided to look at the spring on the pressure relief valve in the oil filter mounting assembly shown in the diagram (a17-0214) provided by walky_talky20. I was able to remove the threaded plug without taking the assembly off the engine. The valve on the opposite end of the spring from the plug is a short piece of steel tube closed off on one end. About half the length of the spring fits into the cylinder.

I fabricated a 1/4 inch steel plug to fit into the cylinder and effectively increase the tension on the spring. It was difficult but I was able to use one of those harbor freight hose removal pliers (long needle nose with tip curved to fit around a rubber hose) along with a large screw driver to pry against the pliers and the plug (compressing the spring) while I turned the plug and was able to get the threads on the plug started. I then finished tightening the plug.

Now that the tension of the spring had been increased, the oil pressure at startup (cold) jumped to about 70. The pressure decreased as before as the engine warmed up but at full operating temperature, the minimum oil pressure was around 28 psi.

I have had no more low pressure trouble since this was done about 6 months ago.

[JPC1.8t]

Sorry for the necro-bump...

First I would like to thank Walky for the detailed information he provided, it is all accurate, the longest part for me was getting the damn test port bolt back in.

Next.. I got the red oil light on a drive around town Thursday afternoon. The light comes on, three beeps, and then shuts off. About a minute or two down the road the same thing happens. I get the car home check the oil and its fine. Let it sit for the rest of the day and go for a drive. About 3-5 minutes into the trip the red oil light is back.

Today I get a test gauge on the car here are the results...


Cold (car was sitting for 24 hours)
Idle: 70
2k: 90
3k: 100
4k: 115
5k: 120

Warm
Idle: 55
2k: 75
3k: 90
4k: 100
5k: 110

Warmer (temp halfway to full operating temp)
Idle: 40
2k: 70
3k: 80
4k: 90
5k: 100

During this round of testing the red oil light came on at 1500 rpm while the tester was reading 60psi, the light remained on through the test phase even while the gauge read 100psi at 5k. When the car was brought down to idle the light came off with the gauge still reading 40psi.

Hot (car at 100% operating temp)
Idle: 30
2k: 66
3k: 72
4k: 82
5k: 90

The same thing occurred this time as last time, light comes on even though gauge readings are good, except this time the light did not shut off at idle.


Based on what I've read about when the oil pressure switch kicks on (16-23psi) is it safe to assume mine is dead.. as long as my gauge wasn't taking horribly inaccurate readings every time?

[walky_talky20]

Those numbers look great, and normal. I would say the gauge is fine, based on it giving the expected numbers, and appropriate range from idle>5k for all tested temps.

You B6 guys don't have the luxury of an oil temp gauge on the dash (but I think you can check in VCDS). I'd bet your "hot" readings were taken at an oil temp of 150-160F or so. At 180-200F you will usually see idle pressure drop below 30psi. You usually need to work the turbo a bit to get the oil temp above 180F, though.

For your last test, it seems the switch must have opened with the revs above 5k. In that case, the warning logic will make the Oil Pressure Alert stay active at all times, and it will not erase until engine shutdown. So that explains the persistence.

Anyway, I'd say you confirmed healthy oil pressure and identified a faulty switch. I would replace the switch at this point.

[JBM]

Sorry for the necro, but I had this first happen to my car today when the wife was driving it. She get's it only at a certain RPM. She said there is no sounds, leaks, any of that, noise. We did get the turbo swapped out.

My wife will see again to see if it was a fluke but this is discerning...any more out of this car and it's going out back behind the shed...

I'm stuck in germany right now so I cannot crawl around but I have to say, I hate this fucking car right now...I could have bought half a replacement.

Good thing I live in a Navy town and I should be able to hark it off.

[customa4]

Have an oil change done and put in a can of BG oil desludge for a temporary fix. It worked for me and I haven't seen the oil light again. I do know the pan needs to be dropped and done properly. It can be picked up from most dealers. I've gotten some from a Toyota, Audi and a VW dealer.

[JBM]

We are getting the car towed to the shop that did the work on it b/c they charged to clean out the water that was condenesate in it b/c of the catch can.

Wife will be driving the Xterra which has not given any issues minus the heater not working during the winter which we got fixed.

Will this fix the issue with the BG?

[yaqui]

We just picked up out 2003 B6 A4 Quattro a few weeks ago, we took it on a short trip out of town. After about 45 minutes at highway speed, I get a red oil can and three beeps on the dash. Pull over at a gas station, check oil while running, and levels are good.

Last oil change less than a month ago. Everything looks okay, so back on the rays for the final 45 minute drive. Car sits for the day and as we are headed back home, highway speed, a little slower this time, the exact same thing happens, 45 minutes into the drive. Kind of curious.

I wonder it is a bad pressure switch? I've read a few pages, and will read some more. Just wanted to see if anyone had my same issue after longer rather than shorter drives.

TIA.

Y