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Crankshaft Sensor Replacement
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Pelican Technical Article:

Crankshaft Sensor Replacement

Nick Czerula


3 hours3 hrs






Set of sockets, 5mm Allen bit, flathead screwdriver

Applicable Models:

BMW 323Ci Coupe/Conv (1999-00)
BMW 323i Sedan/Wagon (1999-00)
BMW 325Ci Coupe/Conv (2001-06)
BMW 325i/xi Sedan/Wagon (2001-06)

Parts Required:

Crankshaft position sensor, sealing o-ring

Hot Tip:

Work with a cool engine

Performance Gain:

Car will run well

Complementary Modification:

Replace your crankshaft

The digital motor electronics (DME) engine management systems in BMW E46 vehicles use the engine control module (ECM) to control fuel injection, ignition and other important drive train functions. The ECM sequentially triggers the fuel injectors to spray fuel into the intake ports and then, a split-second later, triggers the ignition coils to fire the spark plugs. This sequence of events is timed by using the crankshaft position. Using the signal from the crankshaft sensor, the ECM "knows" which cylinder is ready for fuel intake and then, later, for ignition. 

The crankshaft position sensor is located near the starter motor, mounted in the engine block. The sensors read a toothed-reluctor wheel mounted to the end of the crankshaft. It then sends a signal to the DME, which is used to identify cylinder location. If this signal is missing, for example from a faulty crankshaft sensor, then your engine will not start. You can consider the signal from the crankshaft sensor the RPM signal for the DME.

Keep in mind that when your car was serviced before, parts may have been replaced with different size fasteners used in the replacement. The sizes of the nuts and bolts we give may be different from what you have, so be prepared with different size sockets and wrenches. 

Protect your eyes, hands and body from fluids, dust and debris while working on your vehicle. If you are working with the electrical system, disconnect the battery before beginning. Always catch fluids in appropriate containers and properly dispose of any fluid waste. Recycle parts, packaging and fluids when possible. Do not work on your vehicle if you feel the task is beyond your ability. 

Vehicle models change and evolve as they grow older, so the vehicle shown in our illustrations may vary slightly from yours. If something seems different, let us know and share your info to help other users. Do you have questions or want to add to the article? Leave a comment below. When leaving a comment, please leave your vehicle information.

In this article, I will go over the steps involved with replacing the BMW E46 crankshaft position sensor. You can access the sensor from below the vehicle, working on the left side. The photos in this article show the throttle housing removed from the vehicle for clarity. You do not have to remove it to replace your crankshaft sensor.

First raise and support the front of your vehicle safely.
Figure 1

First raise and support the front of your vehicle safely. Remove the lower engine plastic splash shield. The BMW crankshaft position sensor is located below the starter motor (yellow arrow) at left side of engine - disconnect the crankshaft sensor electrical connector by squeezing the release tab and pulling it away from the sensor (green arrow).

Next, using a 5mm Allen bit, remove the crankshaft sensor mounting fastener.
Figure 2

Next, using a 5mm Allen bit, remove the crankshaft sensor mounting fastener. There is not a lot of room, so I used a short 5mm Allen bit with a 1" extension on my 1/4 drive ratchet.

Once the Allen bolt is removed, pull the crankshaft sensor out of the engine block.
Figure 3

Once the Allen bolt is removed, pull the crankshaft sensor out of the engine block. Be sure the sealing o-ring comes out with the sensor. If it stays in the block, retrieve it with a small pick (yellow arrow).

I like to keep things clean so use a rag to wipe the area around the crankshaft sensor then install your new BMW E46 sensor and sealing o-ring. Torque the sensor to engine block to factory specs. Reconnect the electrical connector and install the engine splash shield. Start the vehicle and allow it to idle for about 1 minute. Check that the crankshaft sensor area is free of oil leaks. If your check engine was on, now would be the time to clear any DME fault codes using a BMW compatible scan tool or a code reader. Follow the instructions accompanying your code reader or scanner.
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Comments and Suggestions:
cirrusblau Comments: Since I don't have a way to log data, I scaled out on the time base to capture as much time as possible, and put the pattern on hold several times and scrolled back and forth, watching for any irregularities. Nothing found and running out of ideas, I took up a local forum member on his offer to do a deep scan for codes. After clearing the deep codes that my basic reader couldn't see, the car started right up no more long crank and runs great! Thanks for all the help in troubleshooting. Hopefully this series of posts will save someone else some time!
July 11, 2016
  Followup from the Pelican Staff: Thanks for the follow up. We appreciate it.
- Nick at Pelican Parts
cirrusblau Comments: It's not quite zero, just a bit above. In the couple minutes that I watched the scope, the signal was consistent, so intermittent connection seems unlikely albeit not ruled out. The problem is the same before and after a head gasket. Timing was correct when I started opened the motor, timing is correct after putting it back together. How would one diagnose a DME fault?
July 5, 2016
  Followup from the Pelican Staff: Scope patterns are only good for signal confirmation. You can't find a drop out or failure easily using a pulse train. You will need to graph the frequency over time to see changes in the signal.

Dme , check power and grounds, if good the DME must be faulty. That is is you trust your signal input diagnosis.- Nick at Pelican Parts
cirrusblau Comments: Finally had a chance to continue the diagnostics. I put a scope on it backprobed the connector at the ECU and have a constant signal with good waveform right from the moment I engage the starter. Peak to peak voltage is approximately 5 VDC. Is that the correct Vpp? Is there anything else I can check?
July 4, 2016
  Followup from the Pelican Staff: 5 is normal for most BMW crank sensors. Is the signal reaching zero volts? I can't tell from your screen.

if the signal is getting to the DME, you may have an intermittent connection issue, engine timing or fault with the DME. - Nick at Pelican Parts
cehster Comments: Hi, good day.
Can you please direct me where can I find the crankshaft position sensor on a BMW E46 318i SE 4 door saloon M43TU engine size 1895cc with BHJP 116.7? Is it under near the starter motor or just behind the solenoid?
June 13, 2016
  Followup from the Pelican Staff: We don't have that engine in the US, so I can't be 100% sure. But it should be near the starter motor. - Nick at Pelican Parts  
cirrusblau Comments: Haven't checked signal as I don't have a scope, but I have continuity on 2 of the pins to the ECU and ground on the third. When powered on, I have 5 V and 12 V on those two pins. I've also tried temporarily installing without the seal to ensure the sensor is fully seated. How does the ECU detect a fault? Is there anything else that could cause this fault code? Car is a 2001 330i
June 5, 2016
  Followup from the Pelican Staff: Continuity doesn't confirm signal integrity, as the wires are not loaded or in use during that test.

Each fault code for the component identifies a state. For example, voltage too low, too high or signal erratic.. - Nick at Pelican Parts
cirrusblau Comments: I installed a new VDO sensor, but still have a long crank every time cold or hot and low power. Car is throwing a P0335. Any ideas to troubleshoot?
May 30, 2016
  Followup from the Pelican Staff: What is the year and model of the vehicle?
Have you tested the signal to the DME? - Nick at Pelican Parts
Abi Comments: Thanks Nick, for the response. I pulled the intake manifold off again to do a process elimination. I took the injectors to the injector place to test them again so I can eliminate the leak as a possibility. I am glad I took them in because, they started leaking. 3 of them has a very slight leak. I am not sure if that little of a leak can cause issues, but the injector shops think that is the issue. Will order new injectors and put everything back and test it. Will keep you posted.
May 13, 2016
  Followup from the Pelican Staff: Thanks for the follow up. We appreciate it.
- Nick at Pelican Parts
Abi Comments: Nick, I drive a 03 330I, 5 speed. My car has issues starting when the engine is warm. It starts easily when the engine is cold/hot. After I drive the car and park it for less than 15 min and then try to start, it starts fine. Anything after 15 min to 4 hours, it cranks for a little while and then starts. Replaced fuel pump, filter, fuel purge valve, MAF,coils, spark plugs, both cam sensors, crank shaft sensor, engine coolant temp, vacuum lines, air intake temp sensor, cooling system and starter. I did check the fuel pressure at the rail. with key in ignition position 2, I see 46 PSI and after starting the car at idle, it shows 50 PSI. The pressure stays at 46 PSI for 20 min and then starts to drop and is usually around 15 PSI around 45 min. I am lost. Any pointers on what to look next? Thanks,
May 9, 2016
  Followup from the Pelican Staff: Hot restart issues can be sue to timing or fuel delivery. without a fault code, I can't imagine it is a timing issue. I would check fuel volume as well, it may be low. - Nick at Pelican Parts  
the broke comedian Comments: Had my clutch changed on my 325 XII it's an 02 now the car starts easy when I press in the clutch but one started I can't shift into gears when the car is off I can shift into gears is it the flywheel?
April 28, 2016
  Followup from the Pelican Staff: The clutch is either the wrong part, not installed correctly or you have a hydraulic system issue, it is not releasing the disc to allow you to shift. Give our parts specialists a call at 1-888-280-7799. They can figure out what part or repair kit you need.
- Nick at Pelican Parts
Brandon Comments: Hi, I have an 03' 325i and this is the second time in a two month period I need a crankshaft sensor. The mechanic I go to said that it probably went out do to me buying a sensor from autozone and that i should have bought a Bmw part. that being said when i search "e46 crankshaft sensor" on google about 15 different ones come up from bavarian motor sports... does it matter which one i buy?
March 23, 2016
  Followup from the Pelican Staff: Yes it does. You will want to buy a high quality part from Pelican Parts. =0

Give our parts specialists a call at 1-888-280-7799. They can figure out what part or repair kit you need.
- Nick at Pelican Parts
gammelhagger Comments: Ups.... forgot to mention that the crankcase ventilation is ok, and I have no vacum leaks either....
March 15, 2016
  Followup from the Pelican Staff: got it. thanks. - Nick at Pelican Parts  
gammelhagger Comments: Hi, I have a 2001 330ci that looses power when warmed up. Starts fine, hot or cold.. No codes, and I have changed the vanos, DISA, MAF, cam sensors org. BMW , given it a full tune up, checked live data from Vanos, O2 sensors as well as performed a smoke test... all data is fine... and... when I re-boot the ECU by removing the battery connection, the car runs fine for a while... but the fault returns.. Could I have a faulty crank sensor ?? Again no codes are thrown!
March 15, 2016
  Followup from the Pelican Staff: What is fuel pressure and volume? What is compression? Can you view engine timing when the problem is present and not present? - Nick at Pelican Parts  
Adammc6 Comments: Hi nick. Code is 3E90
March 9, 2016
  Followup from the Pelican Staff: That fault is for no RPM from the crankshaft sensor. The sensor may still be faulty, or the wiring to the DME. Check for the signal to the DME from the sensor. - Nick at Pelican Parts  
Adammc6 Comments: I have a newer bmw and was hoping you could help. It's a E91 325d and am showing a crankshaft sensor fault. The garage changed it for a new non oem part and are still getting the fault. They do not appear to know what's wrong. The car will crank but not start I believe. Can you help?
March 4, 2016
  Followup from the Pelican Staff: What is the fault code? - Nick at Pelican Parts  
honster Comments: My check engine light was on in my e46. It said there was a faulty crankshaft sensor, so I replaced it. Now, it says the crankshaft sensor is giving improbable results,and now it also saws I have a crankshaft tooth fault. Can you please give me any advice? After installing the sensor, it was hard to start. Then, while cold it made one clunk, then drove like a champ. I brought it home and will not start anymore. Sounds like it is close sometimes. Thanks!
February 28, 2016
  Followup from the Pelican Staff: The sensor signal may be faulty, possible wiring issue. i would check if the sensor is sending the signal to the DME. - Nick at Pelican Parts  
Chris Comments: My 2004 x3 was reading code p0340 o I changed cam position sensor,now it's reading codes p0010 and p1338.what should I do?
January 22, 2016
  Followup from the Pelican Staff: You either replaced the wrong cam sensor or there is a problem with your VANOS actuator. - Nick at Pelican Parts  
Dave. Comments: Nick, thanks for your comments.
September 23, 2015
  Followup from the Pelican Staff: No problem. - Nick at Pelican Parts  
Dave Comments: Hello. I have an '04, 2ltr 318i Touring 118k miles. Recently the engine has started to cut out occasionally. Mostly the ignition light will flash on for a split second then off again and the engine will stutter for a second then all will be back to normal again but on 2 occasions the engine has stopped altogether. Once I turned the ignition off then back on again the engine has restarted straight away. At all other times the engine runs ok. I have read elsewhere that this is a sign of a bad crank position sensor and I would like your opinion on this please.
September 20, 2015
  Followup from the Pelican Staff: Sounds more like a power problem. To be sure, check the DME for fault codes. You may have a fault for either the crank sensor or power supply. - Nick at Pelican Parts  
keegan Comments: i have a e39 528i bmw that crank but wont start, theres fuel pressure at the injector there was spark at the spark plug plus i put in new plugs and battery is also new.the rpm meter dont move when i try to start it.does that mean the crank sensor and the cam sensor is gone? the crank and the cam sensor wire look if the crank sensor is bad would you still gets sparks at the spark plug?
September 12, 2015
  Followup from the Pelican Staff: If you have spark, the crank sensor is likely good. Do you have good compression and injector pulse? - Nick at Pelican Parts  
BKL070 Comments: 2001 3 xi. I removed the crank sensor in this vehicle. From what I could see going from underneath is not worth it or even possible. Remove the air box and intake duct boots. There is a small canister mine is black plastic about the size of a food can. Loosen the bolt that holds the canister. You may need to disconnect the vacuum lines on the can, then move the canister out of the way. The crank sensor is under the can.
Note:The canister and lines are, from what I can tell, just for the flaps in your tailpipe. When I did this I did not know. Mine is already disconnected at the muffler. The vac hoses at the canister are going bad. I was able to get it back together but now I am going back to plug the line at the engine.
August 28, 2015
  Followup from the Pelican Staff: Thanks for sharing your installation process and experience. These type of comments add so much to the Pelican tech community.
- Nick at Pelican Parts
Dennis R Comments: 230K '02 330ci. I've replaced fuel pump, filter, cleaned injectors and o-rings, replaced O2 sx, ign. coil, sp. plugs, and checked vacuum lines, replaced throttle boot, oil pr. regulator, and pcv. Still having P0300 code multiple misfires and random cylinder misfires. I can still start the engine but with unsteady idle and will die eventually. If my crankshaft sensor is faulty, will I still be able to start the car you mentioned, the engine will not start. Is it recommended to change both the crankshaft and the camshaft sensor? Thanks so much!
August 8, 2015
  Followup from the Pelican Staff: The engine will not start if the crank sensor is faulty all the time. If intermittent, it could start.

I would check compression. - Nick at Pelican Parts
Michael Comments: I am having a problem starting my 2000 328i, but only after driving a short distance. If I drive for a long distance and shut the car off it turns right back on no problem. After trying from a short distance, the car will eventually start after waiting a few minutes, but drives poorly and hesitates after that. My fuel pump is working and car runs great other than that. It only seems to do this when it is a little colder out, when it is warm no issues. Any ideas?
July 17, 2015
  Followup from the Pelican Staff: Cold start tends to be fuel issues. What is fuel pressure and volume? - Nick at Pelican Parts  
Tom Comments: Hello I have a BMW 325i it was driving fine all day then all of a sudden I'm a the traffic lights and the car failed to gain power and go past 2-3k revs then it would idle by itself then eventually stall then I would start the car same problem rumble failing to get past 3k revs then eventually stall I ran a diagnostic test came up crankshaft cylinder misfire fuel something sorry can't remember but today the car seems to have its power and drive normally after clearing the faults any idea what's going on it's really baffling me
July 2, 2015
  Followup from the Pelican Staff: Sounds like an engine misfire. I would check spark, fuel and compression on all cylinders. - Nick at Pelican Parts  
Costelo Comments: THANKS,great site,very, very informative
June 18, 2015
  Followup from the Pelican Staff: Thanks for the feedback. Glad we could help.
- Nick at Pelican Parts
Costelo Comments: Hi , i want to replace my crankshaft sensor as a preventative maintenance. The current sensor is still 100% good.there are no codes and the car runs fine.
Will i need to reset the DME after i install the new sensor?
June 18, 2015
  Followup from the Pelican Staff: No, you should not have to. - Nick at Pelican Parts  
cmar Comments: hello nick, 2001 325i 200k miles, new wiring harness. the car just stopped running and will not start, engine turns over, will not run. I suspect spark failure as there was plenty of fuel smell when it crapped out. 5 cylinders with misfire codes and both o2 sensor codes and that's all my peak research reader will detect. completely puzzled. reading your tech guides i suspect the crank sensor, but will the throttle positioner sensor also play a role. Thank you for any help
April 1, 2015
  Followup from the Pelican Staff: Throttle position sensor should not cause a not start, it would set a fault code if it were faulty.

I can't help without knowing what is missing from the system when you are trying to start it. When your engine doesn’t start you’ll want to check the basics. Check spark, fuel injector pulse and fuel pressure, volume, quality and engine compression. Are there any fault codes? Once you figure out what is missing, it will be easier to diagnose.
- Nick at Pelican Parts
Willis car ever start again mcgee Comments: Thats what i thought. Here are some more clues to this no start mystery: When i push the start button the engine will continuously crank until i either let the clutch pedal out or push the start button to stop the cranking . Also i cant get any code reader to link to the vehicle. Not even a new matco scanner or even a snap on scanner. i think it was a solus??? anyways, i have bench tested every relay that i could find on the vehicle along with all of the fuses. I cant find a wiring schematic anywhere for this car. Its a 4 door 325i. The manufacture date is 06/2005.
February 7, 2015
  Followup from the Pelican Staff: The cranking scenario is normal, it will crank for a defined amount of time, until it start - or not.

if you can't communicate with the DME, I would this the issue may it. Check if the DME is receiving power and ground, good ignition power. Then check the data lines. If all is OK and the DME is not functioning, it may be faulty.- Nick at Pelican Parts
Willis mcgee Comments: F1 fuse is good. Is the dme relay supposed to power up when the ignition is turned on or does the ecu have to receive crankshaft position signal while cranking before it powers up the relay? Would a bad crankshaft position sensor prevent the dme relay from turning on?? Also what is the purpose of the resistor that is located on the cap for the obd2 port?
February 5, 2015
  Followup from the Pelican Staff: No, the crank sensor would not. The DME relay should be on when the key is in the run position. - Nick at Pelican Parts  
Willis mcgee Comments: Hello pelican i have a 2005 325i that cranks but wont fire. Now here is what i have found: no power to ignition coils while cranking, all fuses are good , plenty of fuel pressure, cant get code scanner to link to vehicle. Ebox fuses are all good. The relay that powers the coils is good.... Im stumped!
February 3, 2015
  Followup from the Pelican Staff: No power to the coils, power comes from the DME relay (located engine compartment e-box) Fuse F1 in the front e-box as well. Start there.- Nick at Pelican Parts  
Greg Comments: My son has a BMW 2001 330ci that started running poorly and dash lights came on. he checked the codes they said bad mass flow sensor and crankshaft sensor. He pulled the connections loose and cleaned them and plugged back in and cleared codes. It seemed to run better for a short time then bad again. He checked codes and it showed an intermittent bad crank pos. sensor again. He replaced the sensor and cleared codes he started it up and ran it for a bit and lights on dash where all on and car seem rough. He checked codes again and it showed fulltime bad crank pos. sensor again and it won't let him clear that code no other codes showing. It still driving poorly low power limp home mode and dash lights on. I read a few places DME and ECU need resetting but that's a shop or dealer thing. Any ideas about problem ?
January 26, 2015
  Followup from the Pelican Staff: I would check the signal from the crank sensor to the DME. You may have a damaged wiring harness. - Nick at Pelican Parts  
vance28 Comments: BMW 3251 1995 when i start it , and it warms up , a min .the timing seems to be off a little. anyThing electric radio, windows exccelerating the pedal,the idle seems to waver its t timing belt, or dcould it be a sensor
January 10, 2015
  Followup from the Pelican Staff: I would start by checking the charging system. Your issue may be low voltage. - Nick at Pelican Parts  
Val Comments: Would this procedure work for a 2004 330ci?
January 1, 2015
  Followup from the Pelican Staff: Yes. - Nick at Pelican Parts  
Sam Shows Comments: My BMW e46 M54 engine 2000 model has a bad take off as well as shutting down in traffic with dead slow speed or when stationery in traffic, however your explanation I conclude it could be the Crankshaft Sensor. Kindly advise before I buy a new sensor?
October 7, 2014
  Followup from the Pelican Staff: I have seem camshaft and crankshaft sensors cause this issue. I would start by checking the DME for fault codes. If the system is not working properly, a fault code will be set. This will be your best bet when diagnosing.
- Nick at Pelican Parts
Tamim Comments: Hi. I have a 2003 325i. Two days ago my passenger window was stuck when i lowered it all the way, took it to my mechanic. Today he told me the window motor is okay but he thinks the crankshaft sensor is bad since the car did not start. he powered the window from outside which worked.
Also, i have the following codes from the engine light:P2240 heated oxygen sensor bank 2, P2237 heated oxygen sensor bank 1, P0174 system too lean bank2, fuel pressure or volume.
can you help explain all this please?
September 4, 2014
  Followup from the Pelican Staff: The codes for the o2 sensors need to be dealt with first, then you can address the fuel trim fault if it is still present. CHeck oxygen sensor operation and replace as needed. Then clear the fault codes and see if the fuel trim fault returns. I do not see the correlation to a crank sensor. - Nick at Pelican Parts  
pauli Comments: The click to order parts takes you to a horn, not the sensor.
July 22, 2014
  Followup from the Pelican Staff: Thanks for catching the link error. I will have it fixed. - Nick at Pelican Parts  
emmanuel Comments: alright cool cool so should i remove the starter?
November 18, 2013
  Followup from the Pelican Staff: If you need the space, yes. - Nick at Pelican Parts  
emmanuel Comments: where are you located maybe i can bring the car to you, and what kind of vise grip, the bolt looks chipped out, also were can i get another bolt n would i brake around the senor
November 18, 2013
  Followup from the Pelican Staff:

Just a small vise grip, pretty standard. They come in all sizes. You can get a bolt from Pelican Parts, Give our parts specialists a call at 1-888-280-7799. They can help you find the right bolt.

If you remove some of the sensor mounting material you should be able to get a better grip.

If there is any hope for the Allen fastener, you can also try to hammer a larger sized Allen bit into the fastener. I always go one size bigger in a fractional sized bit. if you use this method, do not hammer hard on the crankcase. The bit should go in with light tapping. You don;t want to damage the engine.- Nick at Pelican Parts
emmanuel Comments: a vise grip is to big to fit in there remember this is a bmw 323i its in a very tight spot and i do not have a extra bolt to replace it
November 18, 2013
  Followup from the Pelican Staff: If the bolt is rusty, you are going to have to replace it. I have small vise grips that would fit in the space, so that is an option. If you need to make room, you can remove the starter. - Nick at Pelican Parts  
emmanuel Comments: i am trying to replace my sensor on my e 46 but the thing is the bolt is rusted and stripped also chipped out what cant i do ???
November 18, 2013
  Followup from the Pelican Staff: You can use vise grips to grab and remove the bolt. Or break the sensor away from the bolt, the plastic portion of it. Then use vise grips to grab the bolt. - Nick at Pelican Parts  

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