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BMW Camshaft Sensor Testing
 
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Pelican Technical Article:

BMW Camshaft Sensor Testing

Nick Czerula

Time:

2 hours2 hrs

Tab:

$

Talent:

*****

Tools:

DVOM, backprobes, socket set.

Applicable Models:

BMW E90 3-Series (2006-11)

Parts Required:

Camshaft sensor

Hot Tip:

Work with a cool engine

Performance Gain:

Remedy fault codes

Complementary Modification:

Replace sensors in pairs

The camshaft position sensor is used to synchronize fuel injection and as a feedback device for VANOS (variable camshaft timing) control. When a camshaft sensor fails, the check engine light will illuminate and a fault code will be stored. I have seen faulty sensors cause engine stalling and poor engine drivability.

When you are dealing with camshaft position fault codes, be sure to test the sensor and confirm it is faulty. Other items could also set a camshaft position fault code, for example a dirty or defective VANOS solenoid. If you have a fault code for either camshaft position sensor, check the VANOS solenoid first. It is easy to do and could save you time and money. Remove both VANOS solenoids from cylinder head, see our tech article on VANOS solenoid replacing. Check VANOS solenoid for cleanliness and or debris. Clean both solenoids and reinstall. If the fault code for camshaft position sensor goes away or swaps position from intake to exhaust (or vice versa), the fault code is being caused by the VANOS solenoid. Replace the solenoid that the code followed. Here are fault codes you may have if a VANOS solenoid is causing your problem, 2A9A Cam sensor, inlet signal invalid for synchronization, 2A98 (P0016) Crankshaft intake correlation value outside ref range, 2A82 intake VANOS jammed mechanically, 2A9B exhaust camshaft sensor signal invalid for synchronization, 2A99 (P0017) Crankshaft position sensor and exhaust camshaft, correlation value outside reference range, 2A87 exhaust VANOS jammed mechanically.

In this article, I'll go over the steps involved with testing the camshaft position sensors on BMW E90 models.
Figure 1

In this article, I'll go over the steps involved with testing the camshaft position sensors on BMW E90 models. Be sure to work with a cool engine. The intake camshaft sensor is located at the front of cylinder head on the left side (green arrow). The exhaust camshaft sensor is located at the front of cylinder head right side (yellow arrow)

Using a scan tool, read fault codes to determine which camshaft sensor you have to test.
Figure 2

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. Remove engine covers. See our tech article on engine cover removing.

Working at front of radiator support, remove two T20 Torx fasteners from the intake duct.
Figure 3

Working at front of radiator support, remove two T20 Torx fasteners from the intake duct. (green arrows)

Working at intake air duct connection on air filter housing, using a small flathead screwdriver, release retaining tabs on each side and pull duct off.
Figure 4

Working at intake air duct connection on air filter housing, using a small flathead screwdriver, release retaining tabs on each side and pull duct off. Normally-aspirated engine shown. For turbocharged engines, the duct on the radiator support unscrews the same as the previous step, the duct for the air filter housing is also removed the same way, the air filter housing is in a different spot. Follow duct and release tabs to remove duct.

Testing Intake Camshaft Position Sensor

These steps highlight testing the intake camshaft sensor, testing the exhaust sensor is the same.

Then, pull intake duct out of radiator support and remove from vehicle.
Figure 5

Then, pull intake duct out of radiator support and remove from vehicle. (green arrow)

The intake camshaft position sensor is located on the left side of the cylinder head.
Figure 6

The intake camshaft position sensor is located on the left side of the cylinder head. (green arrow)

Working at intake camshaft position sensor, disconnect electrical connector by releasing with a small flathead screwdriver and pulling off.
Figure 7

Working at intake camshaft position sensor, disconnect electrical connector by releasing with a small flathead screwdriver and pulling off. (green arrow)

Testing with DVOM (sensor installed)
This photo shows how and where to release the electrical connector on the camshaft sensor.
Figure 8

This photo shows how and where to release the electrical connector on the camshaft sensor. Use a small flathead screwdriver, lever tab up to release then pull connector out of sensor.

With electrical connector disconnected, unsnap and remove plastic cover.
Figure 9

With electrical connector disconnected, unsnap and remove plastic cover. (green arrow)


Terminal 1 is the sensor reference voltage.
Figure 10

Terminal 1 is the sensor reference voltage. (green arrow) Terminal 2 is sensor ground / signal wire. (yellow arrow) Terminal 3 is the sensor supply voltage. (purple arrow) Wiring color and DME terminal locations may vary. Check your model against a current wiring diagram. Turn the Key ON, but do not start the engine. Connect your DVOM black lead to battery negative, place DVOM on D/C volts. The red lead will be used to probe electrical connector.

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

Connect your DVOM black lead to battery negative, place DVOM on D/C volts. The read lead will be used to probe electrical connector.

Pin 1 = 5 volts
Pin 2 = Ground (0.1 volts)
Pin 3 = Battery volts
Insert a backprobe into terminal 2, the middle terminal.
Figure 11

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 12

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. Remember when removing the camshaft sensor you will have to replace the fastener after you remove it.

Connect your DVOM black lead to battery negative, place DVOM on D/C volts. The red lead will be used to probe electrical connector.

With electrical connector disconnected, unsnap and remove plastic cover.
Figure 13

With electrical connector disconnected, unsnap and remove plastic cover. (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 14

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 close to 0 volts.
Figure 15

In this photo, the wrench (green arrow) is close to the sensor (yellow arrow), so the DVOM reads close to 0 volts.

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Comments and Suggestions:
tc Comments: I have a 2006 BME E90 with n52 engine. I bought it from a dealer who apparently charged it in reverse polarity and damaged several parts on the car. It would not run when I bought it. I've installed a BMW 720A battery, IBS, brake light switch, starter, and fuel pump as I diagnosed each with faults. The car started and would only idle rough and not respond to the accelerator after I installed the fuel pump, then died after a couple minutes and has not run since, but sputters a bit when cranked like it's trying to start. I replaced plugs, and noticed that #1 is getting spark and #2 does to a lesser extent. plugs 3-6 do not show any discoloration. They appear to be damp with fuel and I have good fuel pressure at the rail. I get a cam position sensor code on both intake and exhaust- 2A9A and 2A9F- indicating a short. I removed the plugs for both the cam position sensors and get 5.0v, 0.0v and 0.38v reading from inside the plug with the car powered on, but not cycling the starter. doing this by myself Looking at the sensor with Bavarian Tech tool while cranking the engine shows sensor readings of 0.00v , then briefly 0.38v, then back to 0.00v. Is this correct? I do not see 12v battery voltage at any terminal on the connector as described above. If mine is not correct, where does the voltage come from for 12v battery power? DME, battery fuse panel, interior fuse block? How would you proceed? Thanks.
November 30, 2016
DeadN54 Comments: Hi there, great technical resource this site! I've performed the sensor test by removing them and see the voltage drops from ~5 down to 0 when touching with a wrench... Is this test conclusive that sensors are fine? Still getting the 2A9A error, even after swapping them over intake to exhaust. Also installed new vanos actuators. I guess that leaves me with crank sensor or the more serious cam ledges or worn timing gear? Thanks for your advise!
October 5, 2016
  Followup from the Pelican Staff: Yes, the sensor is most likely fine if it passes the tests shown.

I would assume timing component wear or the cam ledges, yes. - Nick at Pelican Parts
 
Dave Comments: Hi Nick .have already changed timing chain and guides .had two different mackies check timing with appropriate timing tools .maby ill have to change the vanosesintake and exhaust .will be an expensive affair .and might not be the problem .can the sensor on top for the stepper motor have anything to do with this maby its the multi pin one .have changed this sensor already .i give up .or maby oil pressure .Regards Dave
August 26, 2016
  Followup from the Pelican Staff: If the camshaft sensor signal is getting to the DME, it is likely there is a timing issue. Whether in the chain area or VANOS components, you'll have to figure that out. If your mechanic is coming up short, I would get a second opinion.- Nick at Pelican Parts  
Dave Comments: Hi Nick Dave again.the trouble codeis2b63 camshaft position sensor bank 1 outlet .
August 25, 2016
  Followup from the Pelican Staff: Your issue may be worn timing components, chain guides, etc. I would install a timing kit to see if the mechanical timing is off. - Nick at Pelican Parts  
Dave Comments: Hi Nick i have a 2005 e90 n46 motor having problems with exhaust cam sensor diagnostics keeps logging this sensor ..we checked and cleaned solenoids even swopped them around and changed the exhaust cam sensor .still the fault appears .so we swopped the sensors around .still the same fault .put a scope on the sensor and with engine running picking up eregular readings .please help us
August 23, 2016
  Followup from the Pelican Staff: What fault code is being stored? Do you have the BMW and the P-code? This will help me point you toward a possible cause. - Nick at Pelican Parts  
mike Comments: Update and found the problem.

You were 100% correct - the impulse sending wheel is not only loose but also bent. I took out the camshaft sensor and used a mechanics mirror to make a video while rotating the crank. You can see in the video that the wheel is crushed against the timing gear, and there is play between the impulse wheel and the gear. :

https://www.youtube.com/watch?v=EndI_AP5pww
August 8, 2016
  Followup from the Pelican Staff: Awesome, I am glad to help. Thanks for sharing your find and experience. These type of comments add so much to the Pelican tech community.
- Nick at Pelican Parts
 
Mike Comments: Update.

I noticed that any camshaft sensor that is placed in the exhaust position is being physically worn down by abrasion from what I assume is the impulse wheel. See in the attached picture the corners of the sensors appear cut.

I loosened the nut holding the sensor while the engine was idling and I moved the sensor in its socket and could feel the wheel hitting the sensor.

I then hooked up a multimeter and measured the voltage. If i moved the sensor away from the impulse wheel, the average voltage would drop. The sensor was still sealed to the cyclinder head via the rubber seal. At about 2mm distance from the cylinder head, the sensor read an average voltage of about 2.5-2.7 volts, same as the intake sensor. I left it in this position and reset the codes. The camshaft signal invalid for synchronization code remains.

This is bizarre. Could the impulse wheel be out of position? Could it be warped?

I do not have any VANOS solenoid issues. I've tested the solenoids with +12v and they are operating correctly.
August 6, 2016
  Followup from the Pelican Staff: The impulse wheel could be loose. I have seen this before, but it is not very common. Remove the valve cover and check for damage or looseness. - Nick at Pelican Parts  
Mike Comments: Nick,

I've been reading your guides and repair manuals for years for both Porsche and BMW. I want to say Thank you! You're my first resource.

This is my first post. I cannot solve this camshaft problem on E90 BMW with code P0369 - Exhaust Camshaft Intermittent. Sensor tested good. Swapped with intake sensor, still only shows P0369 code and no other codes.

I tested the wiring harness by checking resistance of the ground and of the signal wire. Both read 1.0-1.5 ohms.

Voltage readings with the sensor unplugged, ignition on, motor not running are as follows:
Battery+: 12.00V
Signal: 4.7V should this be 5v?

When the engine is running, the camshaft signal voltage varies between 4.0 and 4.7 volts. This does not seem right to me.

What do you think is going on?
August 5, 2016
  Followup from the Pelican Staff: 4.7 is Ok, it is close enough to 5. If the signal does not toggle to ground, the sensor is not working. Remove the sensor and use a large wrench to see if you can get the signal to toggle to ground. - Nick at Pelican Parts  
PabloCarpio Comments: Hi there,

Problems with my 2010 bmw 328i xdrive, car is cranking up with backfire and won't start. I'm having these codes p0010, p0013, p0016, p13b4... I cleaned selenoids but the codes are still there, should I change both selenoids and both camshaft sensors or this is related to another issue?

Thanks for the help
May 24, 2016
  Followup from the Pelican Staff: Sounds like a mechanical timing issue. - Nick at Pelican Parts  
Grib Comments: Do you know whether I can probe the wiring harness somewhere other than the Crankshaft sensor to test it as the sensor itself is buried under the starter motor. Per the wiring diagram it is pin 29 in connector X60005 - but how do I find it?
March 7, 2016
  Followup from the Pelican Staff: You can backprobe at the DME.
I would grab a repair manual. It will have the connector info and wiring diagrams.

Give our parts specialists a call at 1-888-280-7799. - Nick at Pelican Parts
 
Grib Comments: Hi,
Can the crankshaft sensor be tested in the same way?
February 27, 2016
  Followup from the Pelican Staff: Yes, the voltage changes will be similar, the frequency will be different. - Nick at Pelican Parts  
Fred Comments: Hi Nick , thank you very much for returning my email so fast, hope u do recall my problem that the cooling fan kicks on sometimes in very cold temp. and the engine light and so as crankshaft position sensor... you suggested that I might have faulty cooling fan , just wanted to be clear on that are you pointing at the cooling fan by itself or the sensor ?! you guys are awesome. Thank you
January 29, 2016
  Followup from the Pelican Staff: If you have a crankshaft sensor fault, it is unlikely relate to the fan. It is a separate issue, address it that way.

if the fan has an internal short, it can turn on randomly. Best bet, test function using an advanced BMW scan tool. - Nick at Pelican Parts
 
Fred Comments: I have 325i 2006 e90 recently my radiator fan kicks ON when I start the car in temp of 20-30F which is very cold and the car is running only less than 3mins I'm getting code 2f0d which tells me the fan blinds error something like that and when I turn the car off and restart fan stops!!! Next day engine light comes ON and gives me 2f0d and the camshaft position sensor and No fan is running everything is fine! I cleaned the camshaft sensor and the one next to it. coolant level checked fine. I clear the codes and goes away for a month or so and comes back again... do I have blinds front of my radiator?! I don't see anything .. so would you please educate me that what is going on ?! . Thanks
January 27, 2016
  Followup from the Pelican Staff: There are blinds on some models. You may have a faulty cooling fan. - Nick at Pelican Parts  
Doon Comments: Hi i have bmw e90325i2006 i just change both selonoid and i change the camshaft and the light check engine still on what i have to do bro pls i dont like to se engine check again when installed the cam shaft the car wasnt cool it was warm so does it change any thing on it thnx
November 6, 2015
  Followup from the Pelican Staff: Check mechanical engine timing. You may have worn parts or a faulty actuator. - Nick at Pelican Parts  
miya Comments: On my E90 320i 2006 model,i changed water pump,thermostart ,hv radiator cleaned,chngee sensor on the radiator out let.still a temperature warning light beep when fan start to run,
October 29, 2015
  Followup from the Pelican Staff: 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
 
Michael Comments: Sorry, I have a 2006 325i. I decided to do some more testing after I posted the other night. First I removed both sensor plugs and the car would not start so that told me that at least one of my sensors was good. Then I swapped the sensors around. When I swapped them the long cranking time went away as well as the check engine light. Not sure why the light went away if I have a bad sensor on the exhaust now. I will probably go ahead and order both sensors and keep my one good one as a spare.
August 1, 2015
  Followup from the Pelican Staff: Thanks for the follow up. Let us know how you end up. - Nick at Pelican Parts  
Michael Comments: Sorry my post reads funny because it didn't include the parenthesis I put in there lol. Sorry about that
July 29, 2015
  Followup from the Pelican Staff: No problem. - Nick at Pelican Parts  
Michael Comments: I am confused by this and hope you can clarify it for me.

You say to put the probe in the middle ground/signal wire on both tests sensor in car and out. I tried this and it stayed at 0 small mV reading while turning the crank with the sensor in and with the sensor out of the car using a wrench.

Then I looked at your pictures for the second test sensor out of car and it "looks" like I may be seeing it wrong you are actually putting it on the yellow #1 pin instead of the middle pin like you mention.

When I put the tester on the #1 pin it works just like you mention in the second test 5V wrench away...0V wrench close but I did not try turning over the car with the wrench.


Which is the correct pin to put it on? If the #1 then both my sensors are good and I need to look elsewhere for my problem P0341 error. long crank, loss of power at low RPM but still runs and drives fine for the most part.

If it is indeed the middle then both my sensors are bad. Seems odd the car would still run decent if they were.

The previous owner said a small shop replaced both of the sensors but were stumped when that didn't fix the error light. I am also wondering if the shop may have damaged the computer. The wire pigtail that goes into the sensor was replaced wires cut and spliced in...they are correct though because it looks like they broke the old connector found it below the VANOS solenoid. Is it possible that they messed up the computer if they cut all 3 wires at the same time to install the new pigtail? I still get the 12V on pin 3 and 5V on pin 1. It looks like it was done well because they soldered and used heat shrink instead of just taping it together.

Also to add I left the wire off of the intake sensor and it ran just like it did when it was plugged up so I thought for sure it was a bad sensor but I am confused with the test.

Thanks, any help would be appreciated. Sorry the post is so wordy but I wanted to make sure I didn't leave anything out.
July 29, 2015
  Followup from the Pelican Staff: It does look like I am in the yellow wire, that makes sense, as yellow is likely signal.

You didn't mention what vehicle you have so I can't look at the wiring.- Nick at Pelican Parts
 

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