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DIY: Crankshaft position sensor replacement

188K views 69 replies 39 participants last post by  Jboy_e46 
#1 ·
theres no need to jack the car, everything can be done from the top. and it sucks if you have large hands. ok, first you wanna remove the air box and maf sensor. then take out the adjuster unit, its that little black box on the side of the intake plentum, its only held on by 2 screws and you can pull it strait out. you also have to het all those partitions out that are around the master cylinder. there r diy's for this search for intake elbow removal. there are pix for how to do all this stuff. you need to remove the intake elbow, it comes apart in 2 pieces, you dont need to disconnect the vacuum tubes from the first piece just move it off to the side. the part that connects to the throttle body is harder to get out cuz the screw that tightens it down is really hard to reach. now that you have all of that out. look down and you will see a plastic canister with a vacuum tube going in one side and out the other. this is actually what controls the exhaust flap in your muffler. its only mounted by one nut. take the nut off and the sensor is right under. here r the pix


here r arrows pointing to the two screw holes that hold the adjuster unit and the vacuum canister thing is circled, i had already dismounted it.


here the vacuum thingy is pushed over to the side and the cole for the sensor is circled. the sensor is actually mounted with the cylander portion facing almost strait down. realoem.com has it pointing horizontal into the side of the block. if u notice a broken hose, i used that to fix a vacuum leak i had. the piece leading to the idle air control valve had dry rotted.


here is the sensor mounted, now all u gotta do is put everything back!

its not too hard, it took me about an hour by myself the second time i did it. you should have one of those little super bright led flashlights on hand. the first time i did this i was stumped for almost 4 hours and then my friend showed up with the flashlight and i found the sensor in like a min. thats all i can think of.
 
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#4 ·
Crankshaft Sensor Replacement

I spent about 3 hours getting to the Crankshaft Sensor deep in the engine cavity. When trying to remove the sensor, the plastic top broke off and now the sensor and metal plate that holds the sensor in place is stuck. Does anyone have any suggestions on how to get the sensor out. I have a 2001 BMW 330ci with 120,000 miles on it. I'm thinking that is the original sensor and it's locked in there pretty good. I was thinking trying to get a screw drive in there and pry underneath the metal tab, or maybe some vice grips to see if I can get it to turn. Any ideas would be appreciated.
 
#7 ·
Thanks for the great picture. It is important to note that we are talking about the M54 engine here (325 or 330) in the e46. There are other engines (earlier, I think) that are different as to CPS location.

I still have the question of whether you can get to from bottom of car. Looks like it is below starter, so that is good, but may be just above crossmember or steering rack or something preventing access.

Also, anyone reuse their o-ring? Guess I need to pick one up at dealer. AutoZone didn't provide with their CPS.

BTW, the CPS from AutoZone says Siemens (OEM supplier) right on it and appears to have the BMW logo scratched off the part...same OEM part...$56 vs $116 retail at dealer.
 
#8 ·
Welcome :hi: My pic came from an M54.

I think you can definitely get to it from the bottom...remove the reinforcement plate and that gives you access to a lot of things--even the post cats (TIS talks about removing the exhaust--not necessary at all for post cats). However, what might get into your way with getting a hex socket is the starter's body. You'll probably have to go the allen key route and as for removing the vacuum reservoir, you'll have to do that too, but as BMW_Stu mentioned, it is just one bolt holding that onto another bracket. You'll probably have to do some acrobatics as I have noticed with having to replace a few items in tight spots that is hard to get leverage.

I would not reuse your old O-ring. Just get another one--a buck or two is not worth your headache going back in to fix a leak.

Siemens is the OE supplier...most of these plug into the engine sensors are made by Siemens. The oil level sensor is by Hella.

When I was replacing the radiator and expansion tank, I also noticed that the BMW logo was shaved off of it. Funny how these guys sell the same thing but it's the logo and a sticker that drives up the price ridiculously.

The steering column should be fine. It might get in the way but if you unbolt it, be prepared to have blue threadlocker since they use that on the bolts. Also, I cannot quite recall if threadlocker is used on the bolt holding in the sensor for the crankshaft. I'll have to double check my pics. I do know they used threadlocker for the intake camshaft position sensor though.
 
#10 ·
Great, thanks.

I have a sedan, so no reiforcing plate, only a plastic splash sheild and the triangular tube reinforcement.

What type of bolt is this? Your pic seems to show a Torqx, and RealOEM seems to show a hex, and you mention an allen wrench, so....suppose they can all be different depending on which of three plants and when the car was made. AutoZone printout shows to torque to 4.5-5.5 ft-lbs for whatevery that's worth.

Any others who have done from bottom care to comment please?

thanks,

Bill
 
#11 ·
Great, thanks.

I have a sedan, so no reiforcing plate, only a plastic splash sheild and the triangular tube reinforcement.

What type of bolt is this? Your pic seems to show a Torqx, and RealOEM seems to show a hex, and you mention an allen wrench, so....suppose they can all be different depending on which of three plants and when the car was made. AutoZone printout shows to torque to 4.5-5.5 ft-lbs for whatevery that's worth.
It's a hex, you can clearly see it a sides of the hex key for the socket before it plugs into the bolt head. It's a hex #5. Yours could possibly be a torx, I have only seen it once where BMW did the switcheroo from hex to torx bolt, which was on the ABS pulse sensor for the back wheels. I have been replacing any bolts and nuts that I undo on this car.

I'll get another pic posted of the sensor without the socket in it later tonight.
 
#12 ·
When I dropped my transmission to change the clutch I made sure I had a brand new crank sensor from my dealer in my hands. It is in one he'll of a location, but with the transmission out it it's super easy to change that crank sensor from underneath . Just a tip.
 
#14 ·
I wonder how hard it is to get to with transmission in? Is crossmember or steering rack in way?

I would prefer not to put car up on ramps and remove splash guard to find out if someone on here has done it on an M54 motor in a sedan from the bottom.

I'll go in from the top, but rather go in from below if can avoid removing all that stuff.
 
#15 ·
I've got a question. I get my Check Engine Lights On and after I run test at AutoZone that readers shows "P0639 Camshaft Position Sensor"
So I bought new intake and exhaust sensors. Cost me $160 total at NAPA. At first I replaced exhaust one. After install I started engine and It last for maybe 4-8 seconds and than RPM went down like car is chocking. Exactly the same acting as with old exhaust sensor. So right after I replaced intake CPS and I thought I was all set. After I turn my key I had same situation. In both cases nothing helped and I still have my car in the same condition as before:( I'm very upset.

So what am I doing now? What If I replace crankshaft sensor? Would that solve the problem? And I wonder why reader in AutoZone says "Camshaft" and not a "Crankshaft".
Does anyone had same problem???
 
#20 ·
Just in case this may help someone else. One night on a long drive, low fuel, felt something happen, enginer started sounding odd, losing power. Car would run, but had difficulty starting (long crank period) and ran sluggish. I pulled the code, P0339 crankshaft position sensor fault. I purchased a new crankshaft position sensor from a BMW dealership w/ my BMW CCA discount, thinking I was safe. I replaced the part, accessed it from the top, took a while and was painful due to large arms and hands. Cleared the codes and started my car. It was better, but still not right. I drove it for a little while, no improvement. Finally just took it to the dealership, turns out the new crankshaft position sensor they sold to me was faulty. I just had the dealership replace it b/c I wasn't going to go through all that again, what if the new, new one was faulty?! They didn't charge me for the part, since I had the original box and receipt with me. Nice of them, hunh!

So, if you replace the crankshaft position sensor, clear the fault codes and it still isn't running right, there's a real possibility that the new part could be faulty. I've read of it happening to others on here several times, and it happened to me. It's not BMW's issue, it's a Siemens quality control issue, they make the actual part.
 
#21 ·
so i just got the p0339 code (crank shaft position sensor circuit intermittent) does that mean that the wiring harness is bad or that the sensor is bad cuz i just replaced it with a new one, wiped the codes, and it came back instantaneously.....now what?:censor:
 
#22 ·
When I had the P0339 code, changing the sensor cured the problem. There have been reports of bad sensors (new ones) though. How did you "wipe" the code? I just unplugged my battery for a few minutes and code never came back. If the code was instantaneous (and assuming a good replacement sensor), maybe you didn't get the wire plugged in all the way or bent a pin on the connector?

HTH, Bill
 
#23 ·
I broke the crankshaft position sensor while replacing my starter on 1999 323. I tried putting in 5 allen wrench in to remove, but was not going in the head, so I used 3/16 which went in, but stripped the inside. I tried by bolt remover bit, but it only ate up the inside. Any idea on removing the bolt? This is harder than removing the starter, which was PITA as well. I do have the starter removed, so I do have some space to work with.
 
#25 ·
I tried cutting a line in to get a flat head on it based on suggestions from internet. Also soaked it with WD40 (what I had on hand) and banged it with long prybar and hammer. And head ripped off. Now the screw is headless. I cut off the CPS and used an extractor which would not grip to the screw and just made a divot in the housing. I am thinking of using JB weld to attach a roundhead screw as a post to the divot and then a nut to hold the sensor. What do you think?
 
#28 ·
My vote is getting to it from the top on my 2001 sedan. I tried the bottom, and could get my hand on it, but could not see what I was doing very easily. My car doesn't have the cannister where others have discribed. I only removed the airbox and could reach it from the top/front without too much trouble. Just my 2 cents.
 
#29 ·
After replacing the crankshaft position sensor with an OEM part from a BMW dealer and the car would not start. It would just crank. I checked the wiring continuity which checked out okay. I bought another CPS from Autozone and tried it. This time it would only start intermittently. I decided to take it to a shop and they reported CPS housing was "loose" and they had to modify it to get the right gap distance. Has any one heard of this problem? I already told them to go ahead with the work since I needed the car back running...
 
#30 ·
http://www.winkflash.com/photo/public.aspx?u=cylonred&ic=9458765

Question on the sensor and the vacuum canister. See above link for picture.

Is the bolt for the canister underneath it? I think I see it but I am not sure but I see no way to get to the bolt from above or even enough slack to move it out of the way. I can't even begin to see the sensor at all - from above or below. I have not taken off the DISA - would it help that much if I did? I have been looking now for over 2 hours - maybe I will see if better in the morning but I very much doubt it. Got to take the car off the jack stands and roll it the rest of the way into the garage.

2001 330i 4 door.
 
#31 ·
Is the bolt for the canister underneath it? I think I see it but I am not sure but I see no way to get to the bolt from above or even enough slack to move it out of the way. I can't even begin to see the sensor at all - from above or below. I have not taken off the DISA - would it help that much if I did? I have been looking now for over 2 hours - maybe I will see if better in the morning but I very much doubt it. Got to take the car off the jack stands and roll it the rest of the way into the garage.
Yes, bolt for the vacuum reservoir is below it. The crankshaft position sensor is behind. You will have to remove the bolt holding in the vacuum reservoir in order to access the sensor. It is a 13mm IIRC. The starter is directly above the sensor.
 

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