bmw 540i camshaft position sensor

[bxdinster]

hello everyone i am new here. i have two problems first i notice a lack of power from the car and i got a ses light on checked it, and it says its a camshaft position sensor but the light goes on and off and it sometimes good then sometimes bad im confused because if the sensor is bad it should always stay bad because its electrical.

problem 2 is only when the car first gets started until it fully warmed up if i dont rev it during idle the car shakes and the rpm is all the way at the bottom next to second line. i changed spark plugs i did have a misifire light on , after i changed plugs no more check engine light but it still sometimes feels like its misfiring it also feels like the lights in the interior start dimming while the engine is shaking

thank you any advice would be helpful

[mattmartindrift]

misfire can be related to cam sensor.

and why does an electrical failure have to be on/off. electrical components can fail in a manner to cause intermittent issues. haven't you ever kicked/hit a non-working electrical component to make it work again?

[bxdinster]

yea but only because its does not have proper contact to make a solid connection. and i don't have no starting problems just a lack of power and the light has not been on for 2 days i pulled cam shaft sensor off completely and the car starts up just fine. i wonder has anyone ever had issues with the camshaft sensor and how the car reacted.

[jeffmilarsky]

Change the wire and you will be all set. Simple as that. Just did mine after the SES came on the and the code indicated a fail(ed)ing wire/sensor.

best,
jeff

[544iAe39]

If the only code thrown is a cam sensor, then I highly suggest starting there and fix the known issue first.

[Hivolt540]

Mine was doing the same thing and my mechanic recomended changing the sensor. He did and that fixed it, no more intermittent check engine light.

[hustler905]

Get ready for starting issues, because it gets worse, or at least mine did. It started off with a very intermittent issue, then got worse.

I put a new sensor in, and it did not correct the problem. I didn't even think about tracing the wire to look for a fault ...

[bxdinster]

sad to hear that hustler hopefully doesnt happen to me lol actually once i tried starting the car and it just kept crankingg the engine was turning but wasnt starting pulled the key back and and started up fine. but i guess since im just starting to get these little problems im just gonna change the sensor and see what happens maybe cause its a on and off problem it probably was working when i start it but sometimes fails when im driving the car can be fine then after a while i can sense it i floor the gas pedal the car feels like its pulling 3rd gear even when 1st from the loss of power due to a bad camshaft sensor

[hustler905]

This is what I did:

CEL light - code for a CPS, so I reset the light, and it came back on in 2 months
Same code, so I got a new OEM CPS and put it in
Every second start it seems to come back on

I have to assume there's a weak connection somewhere in that harness, maybe a common ground somewhere along the line? Anybody got a suggestion?

[BlackasNight]

i have the same idling problem. i had my cps light on so i replaced it. still have the idling problem sometimes but no lights have come on...

[bxdinster]

could the coil pack be slowly breaking or once a coil is bad it stays like that?. the idle problem is annoying but once i give gas it gets better and when the car is fully warm it usually goes away try changing plugs at first then coils if that dont work ur car needs help, and hustler did you try changing both camshaft position sensors because there are 2 of them for each bank i heard that they tend to break one after the other.

[mattmartindrift]

could the coil pack be slowly breaking or once a coil is bad it stays like that?. the idle problem is annoying but once i give gas it gets better and when the car is fully warm it usually goes away try changing plugs at first then coils if that dont work ur car needs help, and hustler did you try changing both camshaft position sensors because there are 2 of them for each bank i heard that they tend to break one after the other.

Idle problems are also related to vacuum leaks, MAFS issues and a variety of different things. I would suggest the CPS replacement - it's an easy DIY. Then, let the DME go through a few drive cycles. Now, if you're still having problems, start eliminating other variables such as vacuum leaks, and the MAFS.


Not all electrical parts are the same - the same way wheel-speed sensors/reluctors can be cleaned and they return to normal operation.

I'm fairly certain that the CPS is a hall-effect-type sensor

[ame]http://en.wikipedia.org/wiki/Hall_effect_sensor[/ame]

[hustler905]

Checked for leaks, I couldn't find any but replaced the intake boot anyway
MAF is clean
Replaced the CPS (I only have one, it's an old 540)

Starting is the issue, it idles just fine.

[bxdinster]

have you tried changing the starter at least

yea but its weird that my car idles just fine when fully warmed up and driven only when cold start even if it like 95 percent warm itll stutter a bit never turn off tho it like a medium to light vibration but goes away when car is driven and completely warmed up

[mattmartindrift]

have you tried changing the starter at least

yea but its weird that my car idles just fine when fully warmed up and driven only when cold start even if it like 95 percent warm itll stutter a bit never turn off tho it like a medium to light vibration but goes away when car is driven and completely warmed up

The starter has nothing to do with how the car runs when cold. I simply spins the engine at a rate that allows the engine to sustain itself.

this is the EXACT issue my car has. I believe to have eliminated all other possiblities. I'm back home now and plan to install my new CPS tonight or tomorrow.

[hustler905]

Would you please update when the sensor is in, it sounds like we all have varying degrees of the same issue. I am curious if a new sensor will correct it for you.

[bxdinster]

yea def wonder how you results will be with the new sensor in..

[jamesdc4]

hustler did you try changing both camshaft position sensors because there are 2 of them for each bank.

He only has one CPS on his 98 540.

[bluebmw83]

sad to hear that hustler hopefully doesnt happen to me lol actually once i tried starting the car and it just kept crankingg the engine was turning but wasnt starting pulled the key back and and started up fine. but i guess since im just starting to get these little problems im just gonna change the sensor and see what happens maybe cause its a on and off problem it probably was working when i start it but sometimes fails when im driving the car can be fine then after a while i can sense it i floor the gas pedal the car feels like its pulling 3rd gear even when 1st from the loss of power due to a bad camshaft sensor

same thing mine is doing i just ordered the part today only issue is how do i change it?

[bxdinster]

to change it is pretty easy i dont kno if ur car is 98 or earlier you only have one if its after 98 you got 2 an intake one and exhaust one both are easy to change esp the exhaust one heres the link where diy is posted

http://forums.bimmerforums.com/forum...d.php?t=886595

[zman]

Had the same issue recently. Replaced CPS and it was all OK after.

Before that I had lumpy idle, bad acceleration and a bunch of other related running issues.

[f355spider]

To the OP, don't ignore the obvious. If you have a p-code for a CPS, then get a new one already. They CAN be intermittently faulty, like anything else. So far (knock wood) every P-code I have had, was spot on. I replaced the offending part, cleared the code and it never came back. End of story.

I see this other posts about idle problems, and such....those could be something else completely. There is no way to say that present Pcode has anything to do with another issue. Fix the pcode then deal with the other symptoms, as mentioned previously in post #12.

If you are short of $$$, PM me your address and I will send you a known good used one for free, with free shipping. It is off my 2001 540, so should be identical to what is used on yours. They take all of 3 minutes to swap out.

[hustler905]

f355spider presents a good offer for someone trying to save a couple of bucks on repairs.

Maybe I'm over-complicating things and will order another new one for my car, could be the last one was just defective.

[mattmartindrift]

replaced the sensor. Tada!!!

i only went for a short drive, and I didn't reset adaptations before doing so. however, it seems that the problem is no longer present!!!!!

alright, slight update.

I still have a bit of what seems to be hesitation when the engine is cold, between about 1k-2k RPMs. I don't drive the car hard while warming up - keep it under 3k rpms and under 1/2 throttle. The remaining hesitation is orders of magnitude less; and, I no longer have a misfire in that hesitation range.

The time span for which the engine seems to hesitate is greatly decreased - hesitation doesn't last as long. This could simply be the car pulling timing, or dumping fuel for self-preservation purposes.



Lastly, this could be all mental, but the car seems to pull MUCH better in the high-rpm range.

[bxdinster]

its weird my car hasnt has the camshaft sensor code in over a week