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Discussion Starter #1
So I have a 2001 330i and I've had an intermittent Check Engine Light for a couple of months now. I had a local part store scan the car when it first came on and it came up with a code the lead me to the exhaust camshaft position sensor. After a couple of starts the light went out...as it should with an intermittent problem that is not triggered after several starts.

I was getting lazy and didn't get the part because I was shopping around for the best price. All the while the light would come on and then after 4 starts it would go out.

After a couple of months it started to stay on a little longer than 4 starts, which would lead me to believe that the intermittent problem was becoming more frequent.

About 3 weeks ago I decided to give it an oil change with BMW oil (had BMW oil in it already). After the oil change the light has gone out and stayed out. Go figure. I just save myself a few hundred bucks.

My question is why would an oil change fix an intermittent camshaft position sensor? Should I expect this to return? It's been about 3 weeks now and not once has the light come on.

Would you recommend that I replace the CPS or just wait until it happens again if it ever does?

Thoughts anyone....why would this fix the problem?

Cheers
 

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unplug the sensor and check for oil residues. if you find oil residues, then it means the sensor is leaking oil which is interfering with the electrical contacts on the sensor. if this is the case, then your problem will eventually reoccur. this was the problem with MY sensor, although i can't say it is the exact problem with all faulty ECPSs.
 

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Discussion Starter #3
So I have a 2001 330i and I've had an intermittent Check Engine Light for a couple of months now. I had a local part store scan the car when it first came on and it came up with a code the lead me to the exhaust camshaft position sensor. After a couple of starts the light went out...as it should with an intermittent problem that is not triggered after several starts.

I was getting lazy and didn't get the part because I was shopping around for the best price. All the while the light would come on and then after 4 starts it would go out.

After a couple of months it started to stay on a little longer than 4 starts, which would lead me to believe that the intermittent problem was becoming more frequent.

About 3 weeks ago I decided to give it an oil change with BMW oil (had BMW oil in it already). After the oil change the light has gone out and stayed out. Go figure. I just save myself a few hundred bucks.

My question is why would an oil change fix an intermittent camshaft position sensor? Should I expect this to return? It's been about 3 weeks now and not once has the light come on.

Would you recommend that I replace the CPS or just wait until it happens again if it ever does?

Thoughts anyone....why would this fix the problem?

Cheers
 

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I honestly think it's purely coincidence that the light shut off with an oil change. I'm sure the light's going to come back on and if you've got a code for a CPS I would definitely change it sooner rather than later.
 

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Well my two cents... which is about all is worth haha... is that those generic obd II codes (assuming what they used) are not always "accurate". In fact I believe bmw has there own, more specific codes/scanners.

So guess what saying is that I would go without replacing sensor unless light comes back, but Idfk haha I had a troublesome code that kept coming back on be, every 100 or so miles, then suddenly never came back...

goodluck hope it stays off :)
 

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Discussion Starter #9 (Edited)
if I break my finger, will washing my hands make it heal
well using my newly acquired experiency and extrapolating it to your situation I would have to say yup....but I wouldn't recommend trying it.

I have started to look into oil viscosity breakdown perhaps affecting the situation. Suspecting the new oil provides better contact between the sensor and the camshaft. As the viscosity breaks down the film between the moving camshaft and the sensor gets thinner and with a weak sensor that may be enough to cause it to give faults.

The oil that was in there had only 12000 km's on it (1/2 of the recommended oil change interval) but I like to keep it fairly fresh. Except this past year it took me just over a year to put that many km's on the oil. That's probably a little longer than I would have liked to see the oil in there and maybe that contributed to the viscosity breakdown.

Does anyone have any input on this theory? Would that be possible?
 

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well using my newly acquired experiency and extrapolating it to your situation I would have to say yup....but I wouldn't recommend trying it.

I have started to look into oil viscosity breakdown perhaps affecting the situation. Suspecting the new oil provides better contact between the sensor and the camshaft. As the viscosity breaks down the film between the moving camshaft and the sensor gets thinner and with a weak sensor that may be enough to cause it to give faults.

The oil that was in there had only 12000 km's on it (1/2 of the recommended oil change interval) but I like to keep it fairly fresh. Except this past year it took me just over a year to put that many km's on the oil. That's probably a little longer than I would have liked to see the oil in there and maybe that contributed to the viscosity breakdown.

Does anyone have any input on this theory? Would that be possible?
you clearly does not know how a CPS works thus you would believe changing oil fixes your problem.
CPS uses magnetic field to measure pulses. it does not touch anything just like an electric guitar.
this is simply a coincidence. maybe the plug was loose or the contact was bad. be like a loose bulb socket.
 

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well using my newly acquired experiency and extrapolating it to your situation I would have to say yup....but I wouldn't recommend trying it.

I have started to look into oil viscosity breakdown perhaps affecting the situation. Suspecting the new oil provides better contact between the sensor and the camshaft. As the viscosity breaks down the film between the moving camshaft and the sensor gets thinner and with a weak sensor that may be enough to cause it to give faults.

The oil that was in there had only 12000 km's on it (1/2 of the recommended oil change interval) but I like to keep it fairly fresh. Except this past year it took me just over a year to put that many km's on the oil. That's probably a little longer than I would have liked to see the oil in there and maybe that contributed to the viscosity breakdown.

Does anyone have any input on this theory? Would that be possible?
Changing the oil will not fix your Check Engine Light.

The question isn't if you wash your hands, will it fix your broken finger. The question is, if you stub your toe will washing your hands stop the flow of blood from your toe. It never hurts to wash your hands, but what you really need is something to put on your toe.

It never hurts to change the oil, but what you need is to fix the cam postion sensor.
 

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In the high desert with a Hertz Rental Car
Hahaha I took a Hertz Rental Lexus IS300 up a rocky mountain road in Oman. Was a great weekend until I got it got stuck... after I cleaned it... hours before I was to return it... at the beach... in the parking lot...:facepalm:
 

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Well, it could be that the person was thinking that the viscosity had changed over time. If the oil thins out too much - which is likely on very long oil runs - the ability of the VANOs to respond will be compromised. Those solenoids are hydraulic, remember. If the VANOs is sluggish, it will set that code.
 

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Discussion Starter #15
Finally Simone who understands what I'm getting at. I fully understand the cps is relying in magnetic fields. But between those two pieces is a thin film of oil. when the system is engineered they take that I to account based on the fluid properties. If the fluid properties change then the system is not the same as when it was initially designed.

Thanks for the vanos solution it makes sense in this case.

The rest of you can resume the discussion on whacking various body parts as you see fit.

Bottom line is I need to change my oil sooner I guess. I haven't run it for that long in the past and I guess I won't again.

If I do stub my toe again ( light comes back on ) I'll be sure to amputate it and replace it with anew one.
 

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What kind of oil was in there when it was acting up?

It's hard to imagine the viscosity being so far off it would cause this, unless it was a 0/20 oil. Or it was loaded up with a major amount of fuel from a sticking or clogged injector, or it was a low quality oil that sheared down to a really thin viscosity.

Have you changed the VANOs seals? Could be a combination of weak seals and old oil. Stranger things have happened.
 

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I'm assuming the CPS code is for the cam being out of position. If it's out of position, then it makes more sense to look at what gets it to where it's supposed to be, not the sensor itself. At that point we're talking about the VANOs and the hydraulic system that makes it work. Oil viscosity and the condition of the o-rings that move the cam come into play.

Oil viscosity and hydraulically-actuated variable valve timing come up quite a bit with other manufacturers because of this. The issue gets a lot less attention in the BMW community because we typically choose from a much smaller group of oil; generally we don't have people running anything from 0-20 to 20-50 in the same engine, and mostly everyone is already using synthetic or at least a good dino.
 

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The guy in charge of my high school cafeteria had this car!
Dodge Spirit was my first car, when I was 16. It was a $400 valued gift from grandpa and parents. I spray painted it flat black and put walmart hubcaps on it hahaha :facepalm:


To OP, ignore my first post, just listen to the code n fix it!
 

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I'm assuming the CPS code is for the cam being out of position. If it's out of position, then it makes more sense to look at what gets it to where it's supposed to be, not the sensor itself. At that point we're talking about the VANOs and the hydraulic system that makes it work. Oil viscosity and the condition of the o-rings that move the cam come into play.

Oil viscosity and hydraulically-actuated variable valve timing come up quite a bit with other manufacturers because of this. The issue gets a lot less attention in the BMW community because we typically choose from a much smaller group of oil; generally we don't have people running anything from 0-20 to 20-50 in the same engine, and mostly everyone is already using synthetic or at least a good dino.
oil viscosity?
vanos is purely based on oil pressure. if you oil viscosity dropped to a point to affect vanos, your oil pressure light would be turned on.
also vanos even when bad will not cause cam out of position. sure it adjusts the timing but not that much.
 
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