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Discussion Starter · #1 ·
Hello everyone. I've got a problem. About a month ago I got my oil changed at my local vw dealer. A few days after that I was driving to work when the oil pressure light started flashing red and beeping at me. It only lasted about 30 seconds though, so I stupidly finished my drive to work. It beeped one more time as I was parking my car. I called a tow truck and had them deliver my buggy to the dealer. They checked my car the next day and could find nothing wrong with the oil pressure. They said they drove it around and the light never came on. That was $100.

About half a week after that I was driving my husband to work. It was a 14 mile trip. When I got him to work the oil light beeped and flashed again, then went right off. The dealership was right down the road, so I drove it there. When I got there it was not flashing or beeping at me. They said I could leAve it there overnight to be looked at again, but that it was probably an electrical glitch or something because if something was wrong, the oil light would stay on, and not do this intermittent thing. They said it'd be fi e to drive it home.

That was a week and a half ago. I drive my car everyday and the oil light has come on maybe 3 times, then gone right off.

I noticed that the blue coolant light was also coming on intermittently.

I googled this and saw that some people who had this problem (oil light and blue light) solved it by changing the water temperature sensor.

Is this the route I should go? I am not a car fixer myself, is this something I should attempt or should I go to the dealer and ask them to do it? There is an awesome vw repair in my area, but they are always so booked that it takes weeks to get in.

Am I hurting my car by driving it even though the dealer found nothing wrong, and the light isn't on all the time?
 

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5/23/10 <3
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If the blue light is coming on after it goes off, then yes, I would replace the coolant temp sensor and see if that solves your problems. Otherwise, I say it could be a bad oil pressure sensor, or you have some stuff clogging up your oil pick up tube.
 

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This is identical to the problem I was having recently; the symptoms match exactly to what I was experiencing! I did a step by step thorough troubleshooting and testing procedure on everything; oil pressure was fine but I continued to have issues with the coolant light in my speedo cluster and The oil pressure light blinking, beeping at me! Because, the oil pressure is so crucial to the lifeblood and health of the engine; I was really stressed out about the problem!
I replace the coolant temperature sensor; but the problem was still there, then I tested the oil pressure (with a oil pressure testing gauge), that was in spec, and then I tested, replaced the oil pressure sending unit/switch. The problem was still there; so, then I went back to check the cooling temperature sensor. It turns out when I was replacing the temperature sensor; the wiring got damaged. One of the wires got pulled out of one of the terminals and the plug/connector; that is why the coolant light staying on and this in turn, caused the oil temperature light to blink and beep! I did a ton of research on the web; on one site a Volkswagen technician explained that the temperature sensor circuit; when it has problems or failed wiring issues, will cause electrical "noise" that affects the oil pressure sensor circuit and causes the light to come on and beep in the speedo cluster! I am no electrical engineer; nor did I research orI check out the circuit they were referring to; however, when I repaired my wiring at the coolant temperature sensor and the blue went away after warm-up (it went back to acting like it normally should). This in turn totally eliminated the oil pressure beeping and blinking problem! It has never come back on since then; I consider the repair complete and the Volkswagen technicians explanation, while bizarre sounding, to be accurate and this explains the reason the problem exhibits itself in such an odd way! I would replace the temperature sensor; which is not very expensive and also test and check the wiring plug to the sensor and if it is damaged, repair it.
 

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So, I would replace the temperature sensor and check the wiring, repair the wiring, and clear all the codes, to see if they come back. Then I would run the car and see if the problem occurs again. The temperature sensors are not expensive. If the wiring is damaged; please let me know and I will tell you which parts to buy to repair the wiring harness. I hope this helps; let us know how you're troubleshooting and repair progresses! :)
 

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Discussion Starter · #5 ·
I'm getting the sensor replaced today! Thanks for your input, I'll keep you updated.
 

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Make sure: to have them test the wiring, as well; look in the Bentley service manual. There are troubleshooting procedures and testing steps, to confirm the wiring is working correctly.
 

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Discussion Starter · #7 ·
I got the water temperature sensor changed about two weeks ago... And I'm so happy to report that the oil pressure light has not blinked at all since them. The blue coolant light also stopped popping up randomly. I hope this information helps others with my problem. Thanks for all of your replies!
 

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Excellent! I'm so glad you fixed this annoying problem; you are not alone with this issue, it is terribly confusing to try to troubleshoot! If I had not found the explanation by the VW tech online; I would never have understood the connection between the coolant sensor/circuit and the oil pressure sender/circuit/speedo light! Bizarre but I'm glad someone figured it out and posted the info! The web; can actually be helpful sometimes! LOL! Thanks, Google! :)
 

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What is the connection? I've always been curious.
 

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A Volkswagen technician explained, that the temperature sensor circuit; when it has problems or failed wiring issues, will cause electrical "noise" that affects the oil pressure sensor circuit. This, causes the light to come on and beep in the speedo cluster!
 

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I work in electronics, and we call this FM (F#$*!ng Magic) when weird stuff like this happens.
So, can you explain the "noise" the VW technician was talking about; is it possible, that the oil pressure and coolant temp are in a similar circuit and this link.... causes a bleed over of a signal? I can understand the concept; of a failure, affecting other items in a data bus. For example; many are noticing when there is a "hard failure", of a certain component on the data bus, it can bring down the whole communication or go into a "single wire mode". Obviously, I'm no electrical engineer but the more we work on these cars with so many computers, data bus communications etc.; you start to see failure patterns! This was a case: where I really spent the time troubleshooting all of the components of the system and the wiring failure/coolant temp sensor circuit, ended up being the problem.

Appreciate any insight and thoughts... :D
 
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