I am getting a P0390 Camshaft position sensor with Bank B showing up but was wondering where is this sensor located exactly so I can make sure it's not corroded and faulty. Please someone help me locate it!

I am getting a P0390 Camshaft position sensor with Bank B showing up but was wondering where is this sensor located exactly so I can make sure it's not corroded and faulty. Please someone help me locate it!

This information is taken from the 2004 workshop manual.

Code sets if the ECM does not detect a signal from the exhaust CMP sensor for 10 seconds of engine run time. P0391 is set if the signal output is implausible, so with a P0390 code you have no [varying] signal at all.

Code only clears down after three restarts which all pass the diagnostic test.

As to which bank is is which code, the manual is not helpful. I assume that the higher code is Bank 2 and that P0365 relates to Bank 1.

If Bank B is Bank 2, then that is the left hand bank. (Engine layout is always referenced from the 'flywheel' end looking towards the 'harmonic balancer' end, i.e. if you are standing at the front of your XLR, looking at the engine, the left hand bank is on the right.)

The actuator solenoids have two wires, the position sensors have three wires:
Bank 1
Pin 1 D-GN: 5273 Camshaft position exhaust sensor (1)
Pin 2 GY: 5296 Camshaft position exhaust sensor low reference (1)
Pin 3 YE/BK: 5297 Camshaft position exhaust sensor supply voltage (1) (12Volt reference)

Bank 2
Pin 1 PU: 5274 Camshaft position exhaust sensor (2)
Pin 2 BN: 5299 Camshaft position exhaust sensor low reference (2)
Pin 3 L-GN: 5298 Camshaft position exhaust sensor supply voltage (2) (12Volt reference)

(I don't know what the three '(1)'s and '(2)'s mean unless it is the bank number; looking again yes it is the bank number, there is a mixed up drawing on the intake diagram where I can see what they were trying to do and then looks like they changed their minds.)

The low reference is an ECM internal ground.

The resistance of the CMP is stated as 5ohms, but it doesn't say if this is sensor signal to 12v reference or 12v reference to 0v reference.

The position sensors sit above the camshafts, the solenoid controllers are concentric with the camshafts. They are all at the front of the engine, there are four of each. The inlets are towards the valley, or middle of the engine, the exhausts are slightly lower down and further away from the middle.

HTHs

So with all that being said could it be just that the system never detected a signal what so ever? As I am playing it right now that I should just wait after a few restarts of the engine to see if it goes away? If however it does not go away would you recommend me replacing the sensor?

So with all that being said could it be just that the system never detected a signal what so ever? As I am playing it right now that I should just wait after a few restarts of the engine to see if it goes away? If however it does not go away would you recommend me replacing the sensor?

You need to know that replacing the sensor (or any other fix attempt) will not clear the code down straight away (if a bad sensor is the fault of course), it takes three restarts.

The other information was to help you identify the correct component, and if you are comfortable with basic diagnostic testing, to be able to run some electrical tests.

At this distance I can't advise what is best to do. The vast majority of problems with electrical systems are in the connectors one way or another. A careful visual inspection and clean with proper contact cleaner is a quick, low cost action (do not use WD-40). It might even fix the problem! Don't forget that testing the wiring at the sensor end does not rule out a problem with the wiring between the sensor and the ECM, including the plug at the sensor end. A Tech-2 would help in this situation, though the w/s manual has an extensive set of diagnostic steps that do not use a Tech-2. As the sensor is a hall effect device, these are usually very reliable.

If you were to find (say) a continuous 12v on the sensor signal, then you will have narrowed the fault down to either a wiring fault to voltage or probably a sensor failure (or rare but possible, an ECM failure). Unplugging the sensor will 99.9% tell you which of those was the fault. But that is just one example.

Regards,

If you don't know this, you can switch the ignition on (with no engine start) by holding acc for over 5 seconds.

HTHs

If you don't know this, you can switch the ignition on (with no engine start) by holding acc for over 5 seconds.

HTHs

Is that option you mentioned so I can check after a few restarts that it goes away?

Is that option you mentioned so I can check after a few restarts that it goes away?

Noooo, it was just background information.

If you want to check the voltages, you don't really want the engine to be running. I wasn't sure if you know that you can switch on the ignition by holding down acc for a few seconds, so I mentioned it. It is a diagnostic aid, thats all.

In days of yore, GM cars had a key. This went from off to position one (some equipments) to position two (ignition/run to position three (crank/lamp test). Acc was often reached by turning the key the other way from off, (sometimes you had to push the key in a little way too). As the XLR has a start button with run and acc marked, it isn't necessarily clear how you get to ignition on without the engine running.

Best regards,