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Pelican Technical Article:

Camshaft Sensor Testing

Nick Czerula

Time:

2 hours2 hrs

Tab:

$50

Talent:

*****

Tools:

DVOM, backprobes, socket set, scan tool

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)
BMW 328Ci Coupe (1999-00)
BMW 328i Sedan (1999-00)
BMW 330Ci Coupe/Conv (2001-06)
BMW 330i/xi Sedan (2001-06)

Parts Required:

Camshaft sensor

Hot Tip:

Test a known good sensor to set a baseline for your tests.

Performance Gain:

Better control of fuel injection and engine timing

Complementary Modification:

Replace your camshaft

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 crankshaft position information. Using the signal from the crankshaft sensor, the ECM "knows" which cylinder is ready for fuel intake and then, later, for ignition.

However, in addition to the crankshaft position signal, the ECM needs a signal to distinguish the crankshaft valve-overlap top-dead-center (TDC) position from the TDC just prior to the power stroke. This signal is provided by camshaft position sensors, which help synchronize fuel injection and ignition. In addition, camshaft sensors serve as feedback devices for the VANOS (variable camshaft timing) control. 

The camshaft position sensor is used to synchronize fuel injection and as a feedback device for the VANOS (variable camshaft timing) control. In this tech article we will show you how to test the BMW E46 camshaft position sensors. The exhaust camshaft sensor will be shown in the photos; testing the intake sensor is similar. A faulty camshaft sensor will set a fault code and possibly create engine drivability problems such as, rough idle, engine stalling and misfire. 

During the tests you will see what a working sensor will show. If your readings do not match, replace the sensor.

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.

The camshaft position sensor is used to synchronize fuel injection and as a feedback device for the VANOS (variable camshaft timing) control. This tech article will show how to test BMW E46 camshaft position sensors. The exhaust camshaft sensor will be shown in the photos; testing the intake sensor is similar. A faulty camshaft sensor will set a fault code and possibly create engine drivability problems such as, rough idle, engine stalling and misfire. 

During the tests you will see what a working sensor will show. If your reading does not match, replace the sensor.

Using a scan tool, read fault codes to determine which camshaft sensor you have to test.
Figure 1

Using a scan tool, read fault codes to determine which camshaft sensor you have to test. Shown here, the intake camshaft sensor is setting a fault code.

You can check if your camshaft is currently functioning using your scan tool.
Figure 2

You can check if your camshaft is currently functioning using your scan tool. If you view live VANOS data, there are values for camshaft angle (green arrow). When a sensor is operating properly, this angle will change when engine RPM is raised and lowered. If this doesn't change, it indicates a fault. This test is best performed when you have a camshaft sensor code as other DME system faults can cause camshaft angle not to change Testing with DVOM (sensor installed)

Testing with DVOM (sensor installed): 
Exhaust camshaft sensor is located at right front of cylinder head (green arrow).
Figure 3

Exhaust camshaft sensor is located at right front of cylinder head (green arrow).

Disconnect camshaft position sensor electrical connector by squeezing release tab and pulling off.
Figure 4

Disconnect camshaft position sensor electrical connector by squeezing release tab and pulling off.

With electrical connector disconnected, peel back electrical connector sealing boot or remove plastic cover (depending on equipment) (green arrow).
Figure 5

With electrical connector disconnected, peel back electrical connector sealing boot or remove plastic cover (depending on equipment) (green arrow).

Terminal 1 is the sensor supply voltage (green arrow).
Figure 6

Terminal 1 is the sensor supply voltage (green arrow). Terminal 2 is sensor reference voltage / signal wire (yellow arrow). Terminal 3 is the ground for the sensor provided by the DME (purple arrow). Wiring color and DME terminal locations may vary. Check your model against a wiring diagram.


Turn the Key ON, but do not start the engine.

Connect your DVOM black lead to battery negative. Place DVOM on DC volts. The red lead will be used to probe the electrical connector.

 Pin 1 Pin 2Pin 3 
 Battery volts 5 volts (or 12, depending on year) Ground (0.1 volts)





Connect the camshaft position sensor electrical connector. Peel back the electrical connector sealing boot (green arrow).

Insert a backprobe into terminal 2, the middle terminal.
Figure 7

Insert a backprobe into terminal 2, the middle terminal. Then connect the red lead of your DVOM to backprobe (green arrow).

Rotate engine clockwise by hand using a 22mm socket and ratchet on the crankshaft pulley bolt.
Figure 8

Rotate engine clockwise by hand using a 22mm socket and ratchet on the crankshaft pulley bolt. Monitor DVOM for voltage to fluctuate from 5 volts to zero volts as the engine rotates. If voltage stays at 5 volts or 0 volts while you rotate engine, and does not fluctuate, the sensor is faulty. Sensor voltage should cycle twice per engine revolution, (0-5 volts, then 0-5 volts again, per full engine rotation). Testing with DVOM (sensor removed) You can also test sensor with it removed from engine. Turn the key ON, but do not start the engine. Remove sensor from engine. See our tech article on camshaft sensor replacing. Connect your DVOM black lead to battery negative, place DVOM on DC volts. The red lead will be used to probe electrical connector. Connect camshaft position sensor electrical connector, peel back electrical connector sealing boot (green arrow). Insert a backprobe into terminal 2, the middle terminal. Then connect the red lead of your DVOM to backprobe. Hold sensor while moving a wrench across tip. Monitor DVOM; voltage should fluctuate just as it should when rotating engine by hand.

In this photo the wrench (green arrow) is away from the sensor (yellow arrow), so the DVOM reads 5 volts.
Figure 9

In this photo the wrench (green arrow) is away from the sensor (yellow arrow), so the DVOM reads 5 volts.

In this photo the wrench (green arrow) is close to the sensor (yellow arrow), so the DVOM reads 5 volts.
Figure 10

In this photo the wrench (green arrow) is close to the sensor (yellow arrow), so the DVOM reads 5 volts.

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Comments and Suggestions:
ZaCk Comments: Hi, I got this fauth code ,How can I do
September 19, 2016
  Followup from the Pelican Staff: You can replace or test the signal from the exhaust camshaft sensor. - Nick at Pelican Parts  
StevenLT1 Comments: Hi Nick. Do you know what terminal and where to check to see/confirm the voltage is getting to the DME? Do you have a wiring diagram or not what pin to check on the DME? 2005 BMW 325xi AWD E46. Thanks
June 7, 2016
  Followup from the Pelican Staff: I don't have that info. I would grab a repair manual. It will have the wiring.

Give our parts specialists a call at 1-888-280-7799. - Nick at Pelican Parts
 
StevenLT1 Comments: Additional Information. Sorry need to add I have a 2005 BMW 325xi AWD. I just did a the last test with the sensor in engine and for 1 revolution the voltage stayed at 5v 1 time didn't switch and then 0 volts another time but doesn't switch 2 times during the rotation. Also I have a aftermarket sensor.
June 1, 2016
  Followup from the Pelican Staff: Sensor voltage should cycle twice per engine revolution. You may have an issue still. - Nick at Pelican Parts  
StevenLT1 Comments: Hi I need your help. I am getting the P0341 DTC. I replaced the Exhaust cam sensor and still getting the code. The car is hard to start and seems sluggish. I performed your sensor test and all seems correct. Correct voltage on the harness, sensored removed and tests fine. Any ideals what could be wrong? Please advise thanks!
May 31, 2016
  Followup from the Pelican Staff: Confirm the voltage is getting to the DME. If so, the issue may be with engine timing. - Nick at Pelican Parts  
bkl070 Comments: Definitely back probe your wiring harness. I was getting In & Ex Cam sensor and Crank sensor. I replaced all 3 and came back still crank and Intake. When I got around to probing; the crank was good but the new intake sensor was bad. My old intake was good, old crank bad. I put the old In sensor on and all is good. BMW tried to throw a MAF sensor in there when they checked it. Out of the many times I scanned the code they were the only ones to say MAF. Seems to work fine to me.
March 16, 2016
  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
 
Nigel Comments: Hi, can you help please? I have fault code P3263 on my BMW E46 320d se 2004 and was advised by the AA to change camshaft sensor which I have and no change. I've had a service, changed glow plugs, replaced inline fuel pump and now cam sensor. Running out of ideas and money now. Any suggestions would be very welcome, thank you.
January 19, 2016
  Followup from the Pelican Staff: We don't have your model in the US, so I can;t be certain. However, it seems that fault code is often related to faulty swirl flaps for the intake, - Nick at Pelican Parts  
AKWAD Comments: hello , i have a 2003 BMW 325i , i had a code is p1318 camshaft position sensor B , circuit signal duration after initialization bank 1 .i have changed the both sensor intake and exhaust and still showing ,ANY HELLP
January 2, 2016
  Followup from the Pelican Staff: I would check if the signal from the camshaft sensors to the DME is OK. If so, the issue may be mechanical camshaft timing. - Nick at Pelican Parts  
KSteele Comments: I have a 2000 323I that won't start. It acted like it was going to fire up initially, but now it doesn't seem willing to start at all. The battery is charged and reading over 12 volts. The last error code that came up when scanning was a P1397. I tested the exhaust camshaft sensor as directed above. I only see the voltage drop to 0 one time per full rotation of the crankshaft pulley. Does this indicate a faulty exhaust camshaft sensor?
December 28, 2015
  Followup from the Pelican Staff: Camshaft sensor usually do not cause a nos start condition. 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  
Mbarara Comments: We are based in United Kingdom. We have a BMW 330. E46 year 2004, mileage 107000. Code P0041 camshaft sensor does not clear even after replacing the sensor. The engine will not start when warm. If the Air Mass Meter is disconnected the engine will start all the time but code P0041 will not clear. The Air Mass Meter has also been replaced with a known good one, problem persists. Checked wiring and all seems to be good. Any suggestions will be appreciated.
May 22, 2015
  Followup from the Pelican Staff: Have you confirmed the signal using this tech article? That is the nest step. - Nick at Pelican Parts  

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Page last updated: Wed 12/7/2016 02:19:36 AM