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In August 2019, someone hit and totaled my 2005 Toyota Corolla. I purchased a used 2010 Tiguan. From day 0 it has had issues. I drove the car home but as I got off the highway it screamed and flashed low oil pressure. I pulled over to check the oil but everything appeared fine. The light disappeared instantly with no recurrence. Nearer my home it happened again.

I contacted the dealership immediately and they sent a tow truck the next day and brought the vehicle to their garage. To my knowledge (just what they told me) they replaced a sensor and could not replicate the issue. The issue immediately reoccurred for me once I had the vehicle again. I contacted them again and they asked me to bring it to my local VW dealership and they would pay for the inspection. The VW dealership found no codes despite the incident happening within the last 24 hours.

Now, as Winter approached, the issue seemed to fade and my regular commute is very short (10 minutes) so the issue was not at the forefront of my mind. Even with the issue occurring rarely during this time period the vehicle drove fine. Now that it is back to the warmer months and the quarantine is lifting I’m having to make some longer trips again and the screaming and flashing light is appearing more and more often. I will describe when I have seen it most often and when it does not occur:

A few baselines:

  • The oil is full
  • VW said the pressure was fine in their tests and again no codes
  • I also checked for codes within an hour of warnings - 0 codes found
  • It never occurs at highway speeds
  • It never appears within 20 minutes or so of driving if the car is cool
  • I believe it is more likely to appear when my foot is off the accelerator not necessarily breaking
  • Breaking seems to make it more likely to appear
  • Taking sharper turns or going downhill make it more likely to appear
  • It occurs more when hot

Currently it has 5w-30 in it which is in spec. I do not know if this is related because I do not know what was in it before it was last changed since I did not own it but it was still having issues then.

As an example, I drove to my parent's house a couple of days ago for my birthday and the vehicle was fine getting to the highway ~20 mins. Getting off one highway onto another on a 270deg ramp breaking it went off. No problems on that highway and then once off it went off very often at almost every slight slowdown. I pulled off into a parking lot to let it cool down for ~15 minutes to hopefully finish the rest of the way in peace. It went off once more after ~10 minutes more driving before I got where I was going.

It’s clear to me that whoever originally got rid of the vehicle must have had this issue. The carfax was immaculate. It was effectively a 1 owner car and they had taken it to the dealer for every 10k mile recommended maintenance. I would not have seen this during the test drive as I mentioned it takes some time and is more likely under certain conditions. I do not know what responsibility the dealer has to fix this issue. My understanding is the law is quite lax here and does not protect the buyer much if at all.

Pretty lousy situation for the first car I bought (the corolla was given to me. may she rest in peace.)

What should I do?

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    Check the engime wiring for chaffing - sounds like a damaged wire...
    – Solar Mike
    Jun 23 '20 at 14:03
  • @SolarMike thanks for the reply. Anything in particular about what I describe make you think this?
    – CircArgs
    Jun 23 '20 at 14:54
  • This is an answer @DavidSupportsMonica, I'd write it myself but you already have.
    – GdD
    Jun 23 '20 at 17:23
  • @GdD Thanks for the encouragement. Suggestion taken. Jun 23 '20 at 17:42
  • No help, but I had a Audi that the oil light was always on and the dealer could not fix it . I just remembered to check the oil level regularly. Jun 23 '20 at 21:08
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The items that suggest intermittent wire chafing to me are its occurrence intermittently, "when braking," and during "sharper turns or going downhill."

In each of these, the driveline and motor will move around on their mounts as the car goes from accelerate/steady state to braking's deceleration. Physical movement of stuff within the car body could easily cause a wire to move and intermittently make a connection.

I'd look specifically at the wire(s) to the oil sensor(s). I'm not familiar with the Tiguan motor. Oil sensors are typically located hear the motor's oil pump, which is usually low in the block, or screwed into the block where the sensor can "read" what's going on in an internal oil passage.

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  • While this is great information, to make it better, you might display information as to where to look for the oil sensor(s) and wire(s). Not only could it help the OP, but whomever might come in behind them with the same type of question. Jun 23 '20 at 17:58
  • @Pᴀᴜʟsᴛᴇʀ2 You're absolutely right...and I have no experience whatsoever with a Tiguan. I can (and will) amend, but I can't offer much info. Jun 23 '20 at 18:01
  • @DavidSupportsMonica The fact that it is also temperature dependent seems to suggest it's not an issue like this correct? I have never had the issue occur below full engine temp and the frequency of occurrence increases tenfold between these warmer months (I'm in CT by the way) and the winter months
    – CircArgs
    Jun 23 '20 at 18:02
  • @CircArgs Not necessarily, IMO. A wire's insulation could remain relatively resistant to movement when cold. When warmed, it could get softer and allow movement and an electrical connection. Jun 23 '20 at 18:04
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    @CircArgs, while the engine is on I would (very safely) move the wire that connects to that sensor and look to see if I can re-create that problem. Try moving the connector harness, the wires, press the wires together in case there's chafing, be thorough. If you get an oil warning light doing that I'd say you've found your culprit. You may need someone to sit in the car and watch for lights while you do that. If it is hard to reach you can tie some string to it.
    – GdD
    Jun 24 '20 at 7:43

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