2003 Altima 2.5 Crank Position Sensor

[cblazer]

I have found out since purchasing a Service Manual for my vehicle that I have been replacing the Cam Position Sensor with a Crank Position Sensor ...all the while wondering how this could be because I only could see one sensor.Admitting that I am and have been wrong on this I now am focusing on the fix.I am purchasing a cam position sensor and a crank position senor. I am going to replace the cam position sensor with the CORRECT cam position sensor.

Now this brings me to the Crank pos sensor that I have not been able to find.Now after having a Service Manual and spending some time looking for the crank position senor I have found it. Now I have another problem.I am unable to get a socket on it. I shined a flash light down on it and used a mirror to get a good look at it and I really do not see any reason why i cannot do so.

I want to pick your mind and ask you if I need to access this from underneath the vehicle after raising it up or is this really something that I need to let Nissan do?

I am really embarassed to admit what I have done wrong. I take responsibility for my actions and now and focussing on the solution.I was all ready to go last weekend and spent an hour trying to figure out how to get a socket on this thing. I can touch it and it is just really ackward getting to it from the top. I am now at the point where I am starting to think I will have to reach this from the bottom and I just wanted to make sure I do not waste my time trying to do so and that is why I am asking for your experience in replacing the crank position sensor.

Thanks for all your help.

Sincerely,

Sam CederasRaleigh, [email protected]

[Cyclemut]

Yes, you can get to it from the bottom side. Granted, it's still a PIA to get out, even after the bolt is removed, but you can get to it. Be really careful when you start the bolt back in after installing the new one. It's easy to cross thread.

By the way, why are you replacing it? Engine won't start?

[cblazer]

Service Engine Soon Light. Dealer said they were not getting a response from that Circuit and wanted to replace it but wanted too much money.This is after I had told them that I replaced the crank position sensor twice all ready but in reality because of my mistake I was replacing the Cam Position Sensor.Rather than take it back to the dealer and tell them the truth and see if they will replace it for free under the recall I am just going to replace it my self since it only costs $21.

Long story short. I made a mistake. THe car is still showing service engine soon every once in a while. I am going to replace both sensors with correct senors and see what happens then. Crank Position Sensor was never replaced.

Thanks,

Sam CederasRaleigh, [email protected]

[cblazer]

please see the posts I entered in the thread labeled "2003 Altima 2.5S stalls when idling". I solved my problem as described in the post listed above.Thanks,

Sam CederasRaleigh, N.C.2003 Altima [email protected]

[RICERMAN]

Look on the transmission side for the crank position sensor near the front. Dont forget that sometimes its not just the sensor but the activator for the sensor or both. For example on fords the cam position sensor cost about 40 bucks but the activator thats mounted to the engine cam cost about 150 bucks,total =about 200 bucks and not a 30 minute repair.

[Cyclemut]

Look on the transmission side for the crank position sensor near the front. Dont forget that sometimes its not just the sensor but the activator for the sensor or both. For example on fords the cam position sensor cost about 40 bucks but the activator thats mounted to the engine cam cost about 150 bucks,total =about 200 bucks and not a 30 minute repair.

Well, since this isn't a Ford, there is no "activator" for the sensor. Just the sensors.

[RICERMAN]

If it has no activator what makes it work?........you need to tell us poor wantabe mechanics so we can learn

[cblazer]

In case you were not able to read the post I made reference to...I am posting it here also so I am not misunderstood or misinterpreted. Not sure how Ford got introduced in this thread.Thanks,Sam CederasRaleigh, N.C.

------------cut and paste is below-------------------

I just got home from a friends garage. I finally was able to replace the crank position sensor. Boy it was somewhat a pain. There was no way to access it from underneath even though someone on this forum told me you could. I was not able to do so.

What turned out to be the biggest problem was the connector securing the wiring harness to the sensor. Unlike the camshaft position sensor connector, the crankposition sensor was secured to the harness via some push button green colored assembly. Once the green button was depressed ALL THE WAY DOWN I was then able to pull the connector off. Then AND ONLY THEN was I able to get a 10mm socket with extension on it thus being able to remove it.

I had to take the air horn and baffle off and then I used a large tie wrap to secure out of the way to heater hoses. Then I was able to get my arm down between the firewall and the block and do what I mentioned in the paragraph above.

Once I got the sensor out I saw why it was sending a trouble code. There was oil all in the area where the electrical pins are on the sensor itself. I am not talking about the oil all over the body of the sensor that it immersed inside the crankcase and should have oil on it...I am talking about the outside housing of the sensor area where the 3 electrical contacts pins are which are surround by a little shroud and if any liquid gets in there it goes no where and just puddles up if you will.

I am so happy to have finally tackled the problem. Time will tell if all is well. I still have to get a new camshaft position sensor because as I mentioned before I replaced the cam position sensor with a new crank position sensor all the while thinking I was working on the crankposition sensor as I only saw one sensor thinking it was the only one. Now that I have FINALLY located and replaced the HARDEST of the 2 sensors...I will now buy a new camshaft position sensor and install it where it is supposed to thus finally finishing.

At least the hard part is over (crank position sensor) because the cam positions sensor is a piece of cake to get to.

Thanks to all who have helped. I hope my post might help someone else and save them from doing what I did wrong.

Sam CederasRaleigh, N.C.2003 Altima 2.560k

[RICERMAN]

Im waiting to hear how that sensor works. Does it know where the crank is by using a crystal ball or telepathic transmission? I think maybe a do-hickey mounted on the flywheel might work along with this sensor but I was told thats not so........Any car that has the OBD11 system works the same as others,,,,,wheather it be a ford a chevy or a KIA.thats how ford got mentioned,,,,,,,,,didnt you know this? It became a law back in 1996

[Cyclemut]

Im waiting to hear how that sensor works. Does it know where the crank is by using a crystal ball or telepathic transmission? I think maybe a do-hickey mounted on the flywheel might work along with this sensor but I was told thats not so........Any car that has the OBD11 system works the same as others,,,,,wheather it be a ford a chevy or a KIA.thats how ford got mentioned,,,,,,,,,didnt you know this? It became a law back in 1996

The only law that became effective in '96 was the diagnostics portion of the OBDII emissions system. All other facets of the manufacturers are still their own. If the O2 sensor has a failure, then a code for the O2 sensor will come up under the generic scan tool reading. But a manufacturer can still have a specific code for a specific failure of the O2 sensor if it so desires. As long as it still has the generic code available for the generic scan.

Nissan does not have a sensor actuator. Period. There is no discussion on the matter, as it doesn't exist.

The crank has a sensor wheel on it, at the back, inside the block. To change the wheel, you would have to replace the crank.

As far as the sensor goes, I have never, ever replaced it from anywhere but under the vehicle. I have a 90 degree screwdriver that I use as a prybar for the green lock. I push against the axle for leverage and then the lock goes down. Then I use an extension with a 10mm wobble with my 1/4" drive ratchet and remove the sensor. I usually have to use a pair of needle-nosed vice grips to remove the sensor, but since it's bad, and the directions in the recall say it has to be destroyed anyways, it's a non-issue.

I've been working on Nissans for a long time. There is always a trick.

[Cyclemut]

If it has no activator what makes it work?........you need to tell us poor wantabe mechanics so we can learn

As far as what makes it work, it's a magnetic pickup sensor, just like the cam sensor, and most all other position sensors used in ABS and the like.

[Ramius83]

The crank and cam position sensors work by electromagnetic induction. The sensors have a magnetic electric material installed in them. As the teeth on the ring gear on either the transmission flex-plate or the cam gear pass by the sensor, it induces an electric signal to the sensor. The computer monitors these "pulses" that the sensor creates and it determines cam timing, RPMs, timing advance/retard, etc.

And just to let you know, you may want to take a trip to your local Nissan dealer. There is a campaign/recall where we replace both the cam and crank position sensors. Your vehicle may apply to this campaign and you can get a set of free/new sensors installed.

[RICERMAN]

So the only thing that can break is the screw in sensor?

[Cyclemut]

On the crank position sensor, yes, either the sensor or the wiring itself. We have had a couple of issues with field mice chewing through harnesses. That's the price we pay for living so close to nature.

But it goes with a deer attacking my Dad's truck and puncturing his A/C condensor as well. Not your every day occurance.

[RICERMAN]

Lordy. I would be learning how to cook up some deer meat...that sucks

[kmelsr]

I just joined your site, great information.

I have to change the crankshaft sensor too on the same 2.5L altima.

I saw the sensor show by in the back on the engine you have a hard time getting to.

My issue is the Cam and Crankshaft sensor say they are the same but I do not see the same sensor in the crankshaft location as the CAM sensor on the side on the engine.

I included a picture of it. So unless I am in the wrong location which I believe I am correct then something is different with mine.

Any comments or help would be appreciated. [IMG][/IMG]

I guess I can not include a picture of it.

The contactor pushes on the top and the sensor has a screw 12mm in the center on a black plastic piece that bolts into the block I recall 2 wires going to it.
Modified by kmelsr at 3:29 PM 7/27/2009

[digitaldxing]

Here's some pics of my 2003 Altima Crankshaft Sensor. Often mistaken by the Camshaft Sensor because both are identical sensors. They are each located in different locations. I've seen diagrams with the WRONG labeling. Again, this is so confusing for even a mechanic to understand because both sensors carry the same part number which is rare. http://x.nissanhelp.com/forums....html