To locate the speed , and crank shaft censure on 2003 nissan alti

there is only one crankshaft sensor so you will be looking for a CAM shaft sensor for it to be on bank 2
go google and type in --location of cam shaft sensors on nissan altima engine ---

There is one crank sensor and it is: 1) Looking at the front of the car it is on the back side of the engine. 2) Just behind where the flywheel is located.

hope this helps

Hello irmagrita
The speed sensor is located on the right front front of the transaxle near
the right axle flange. With automatic transmission.

On the manual trans. it's located on the transaxle.
I hope this helps.

Change the Throttle Positioning Sensor.
Clean the Mas Air Flow sensor with carburator cleaner, carefully.
Vitally

The engine speed signal code is generated from the crank sensor. The crank sensor is located on the back side of the engine block. See image.

Thanks Jay!

Most likely inside the timing cover, behind the harmonic balancer.

1st, Nissan had a recall on Crank position sensors for 2002-2006 Altima's. Check with you dealer before you go doing any repairs. You may discover you can get your car repaired at no charge.
NHTSA Campaign ID number :O7V527000
Symptom: Erratic behavior. Stalling and no starts and very difficult to diagnose due to the time frame in which the component actually malfunctions. The warranty should not be limited to the original owner.
I would also need more specifics as to which engine you have so I might assist you in where the location of the sensor is. The Altima had a 4 and a 6 cyl engine offered that year.

I believe if memory serves me right its on gear box housing , in slightly different areas depending on gearbox

I have 10 years experience in a Nissan dealership and I know without a shadow of a doubt that the Crankshaft Position Sensor is NOT located next tp the crank pulley... it is rather at the other end of the engine near where the transmission bellhousing bolts to the engine block. It is on the side toward the firewall near the bottom. Even if you can get the vehicle on a lift and get under it, you can't really see it... It's more of a feel thing... There was a campaign (recall) on these engines to replace Crank Position and also Cam Postion sensors. Check with your dealer- the campaign might be open. You will need your VIN number when you call.