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Discussion Starter · #1 · (Edited)
I'm having some difficulties with my 2003 325i sedan. The car has almost 90,000 miles on it and recently the red oil pressure light came on while idling at a red light. The light would turn off once I accelerated. I've done a lot of searching on here but don't know what else to do. I brought the car into my local BMW dealership and had they performed a pressure test ( results came back that pressure was good). They said I needed a new oil pressure sensor (located in the engine). I replaced the sensor, however, the light came on the first time I drove it a few days later. I noticed the light only comes on when the car is idling in Drive or Reverse and that the RPMs seem to be hovering around the 500-550 mark at this time. If I put the car in Park the RPMs increase slightly and the light goes out. I called the dealership again and they want me to bring it back in to be examined again. They mentioned it could be another sensor located in the oil pan? Im just wondering whether or not it is just the ICV. Any suggestions?
 

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Discussion Starter · #4 ·
I assume the oil is the correct spec, as I get the oil changed at the BMW dealership. The last oil change was approx 2 months ago.
 

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2016 340i xD 6-spd
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As odd as it sounds, one thing I'd look at is the end of this sensor wire in the e-box. It heads into one of the multi-connectors in there.

I found oil under my connector and my mechanic said he'd seen it before where the sensor leaks into the wire, pushing oil up inside the insulation...that might affect the voltage it's showing.

Also, nothing personal, but there's also a temp sensor on the ofh...I have no idea if they're interchangeable, but it wouldn't surprise me if they were...so you sure what you took out looked the same as what you put in? You sure you reconnected whatever you disconnected?

Also, since you're having the dealer change your oil, I'd mention that I think your car might get to be very expensive to maintain...oil is very easy to change and it gives you a chance to look around underneath yourself...which is always a good idea!

Among my other random thoughts, I'd say you should check your pulleys and belts--and since your idle is low (s/b around 700) I'd read up on cleaning the icv/tb and making sure you're otherwise up on 'Inspection' work--plugs, filters, etc.

Sounds like because you're idling so low, your oil pump isn't doing the work the car wants it to do. I doubt the oil is wrong, but it couldn't hurt to ask...

Oh, finally, don't think anyone mentioned this but you should check your oil level, of course! Next time you change the oil yourself, btw, might want to calibrate your dipstick in case it's the wrong one. If your oil level is just at max level on level ground in the a.m., and everything else is fine, then you might consider trying to add just 1/4 qt. of oil.

The red oil light can be oil pressure, but it can also be just a low oil level.
 

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Discussion Starter · #7 ·
I just checked the oil this morning, it is right on the top notch of the dipstick. As for the oil pressure switch, I had the dealership replace it so if the problem persisted I could bring it back and (hopefully) not pay to have any more diagnostic fees since the problem wasn't properly diagnosed. I will have them take a look to see if there is oil under the connector...oddly enough, when I had the pressure switch replaced last week they also shampooed my engine which I didn't notice until I arrived home. I think my car is due for an Inspection 2 within the next 9000 miles so it could be something as simple as spark plugs or filters. Also, I checked my invoices, they read that the dealership uses Bulk BMW Syn 5W30.
 

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Many U.S stealerships use the incorrect oil such as Mobil 5W30. I'd be asking the question.
I have NEVER heard of a BMW dealership using incorrect oil...are you just making stuff up?

@OP the oil pan sensor only measures the level...it would cause a yellow not red light
 

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^truth. I wish misinformation wasn't so prevalent on BMW forums :sigh:


Could be a few things, first thing you need to do is mechanically see what pressure is actually coming to the sensor.
Is it a flicker only when hot?
 

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I have NEVER heard of a BMW dealership using incorrect oil...are you just making stuff up?

@OP the oil pan sensor only measures the level...it would cause a yellow not red light
Forum members have posted that their stealership used M1 5W30 which doesn't come close to meeting spec. Learn how to use the Search function here
 

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Discussion Starter · #13 · (Edited)
Yes, the light flickers. It is only when the engine is hot AND when the engine in in Drive or Reverse....NOT in park or neutral.

I drove the car again today and the light did not appear.
 

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meh. i would just bump the idle to get the light to stop flickering. i have seen guys at the dealership go round/round with this stuff..... oil pumps/senders/clusters/etc.etc.
 

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I had the same problem, your idle speed is too low! The oil pump is not turning fast enough when you are at idle. What happens is your engine reaches operating tempature, the oil is hot and thins out, less oil pressure. An idle speed of 500 rpm is too low and the oil pump is not pumping as fast, oil pressure light starts to flicker.
You need to increase your idle speed wich can be done with software. I did not replace my ICV I used a Vedis scan tool to increase the idle speed. Take it back to the dealer and have them make idle speed adjustments.
 

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Just had this problem, It was the Oil Level Sensor. Easy DIY change it on our next oil change. Red oil light would flicker when coming to a stop and stay on when in idle. Eventually turning off when i gave it gas. Only happened occasionally when the car was warm and about 6000 miles on the oil.
 

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Yea..... not the oil level sensor.....


Also I don't think the ISTA can do an idle adjustment last time I checked. I know an autologic will :)
 

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Forum members have posted that their stealership used M1 5W30 which doesn't come close to meeting spec. Learn how to use the Search function here
A BMW dealership used Mobil1? I did use the search function, nothing came up. Why would a BMW dealership even have Mobil1 in stock? They only sell BMW oil. I've specifically asked my dealer before and all they stock is their own oil.
 

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Discussion Starter · #19 ·
meh. i would just bump the idle to get the light to stop flickering. i have seen guys at the dealership go round/round with this stuff..... oil pumps/senders/clusters/etc.etc.
Yeah I will tell the dealer to take a look and adjust the idle speed. I hope they don't to charge me another diagnostic since they obviously were incorrect with the sensor. Its very annoying to see the oil light come on. My friend has an identical car (same year, options, colour...) and the dealer ended up making them get all new senors and switches AND replace the oil pump..and the light still come on occasionally!
 

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Like I said I don't think an ISTA can adjust it, you need to find an Indy with an autologic
 
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