Camshaft sensors both replaced as OBD err error read P0340, turning over not starting

[Mikero]

Aveo 2011 replaced both Camshaft sensors, OBD still showing P0340, turning over not starting. Any ideas?

[avguy]

... Any ideas?

Have you tried to diagnose electrically?

[Ken Jaworski]

Aveo 2011 replaced both Camshaft sensors, OBD still showing P0340, turning over not starting. Any ideas?

I would say that if you think you have had to replace both camshaft sensors and didn't resolve that 340 code, you may be just tossing parts at your engine playing a guessing game costing you money. OBD codes come up with just general information sometimes not even giving you the right clues. I would be looking at electrical connections including the crankshaft position sensor. There is a possibility that the crankshaft position sensor is not functioning or its electrical connection isn't making good contact. The crank and camshaft sensors work together as a set when information is fed into the ECM.

This is a general explanation of how the system works:
The Camshaft Position Sensor is an electronic device used in an engine to record the rate at which the camshaft is spinning. This information is used by the Engine Control Module(ECM) to control ignition and fuel injection. The camshaft position sensor senses the retraction of camshaft (intake) to identify a particular cylinder. The camshaft position sensor senses the piston position. The sensor system consists of a rotating part, typically a disc, as well as a static part, the actual sensor. When the engine is running, the high and low parts of the teeth cause the gap with the sensor to change. The changing gap causes the magnetic field near the sensor to change. The change in the magnetic field cause the voltage from the sensor to change. When the crankshaft position sensor (POS) system becomes inoperative, the camshaft position sensor provides various controls of engine parts instead, utilizing timing of cylinder identification signals.

[avguy]

I would say ....

Not writing this to be critical in any way of what you wrote. Just that it made me laugh a bit, because it reminds me of what I used to do when I first started using these forums years ago. Back then I would take the time to write a bunch of stuff, and (far) more often than not, there would be no reply from the OP. Nothing. So as time went on, I wrote less and less on my first post. Now I just basically 'ping' the OP to see if they're willing to have a conversation. Most of the time there is none, but every once in a while someone surprises me and actually does communicate. The short first reply has saved me a lot of wasted time and frustration.

I'm guessing that you're new to the way these forums are, but perhaps I'm wrong about that and you just enjoy spending time writing. If that's the case - have at it, because sooner or later others might benefit from what you post. But in any case, it's always nice to see someone new who's willing to contribute to these typically very 'quite' forums, so welcome!

[Ken Jaworski]

Yes I am new here so you get a point on that one. LoL However being a retired college teacher now working for GM at the Parma Metals plant, I still tend to give long and hopefully informative responses. It's up to the OP if he or she reads it or not. The real test is if the OP can solve the problem.

[Mikero]

I have not tried this, I will thanks for the response.

[Mikero]

Thanks will do, appreciate the feedback!

[Mikero]

[QUOTE=Ken Jaworski;206356]I would say that if you think you have had to replace both camshaft sensors and didn't resolve that 340 code, you may be just tossing parts at your engine playing a guessing game costing you money. OBD codes come up with just general information sometimes not even giving you the right clues. I would be looking at electrical connections including the crankshaft position sensor. There is a possibility that the crankshaft position sensor is not functioning or its electrical connection isn't making good contact. The crank and camshaft sensors work together as a set when information is fed into the ECM.

This is a general explanation of how the system works:
The Camshaft Position Sensor is an electronic device used in an engine to record the rate at which the camshaft is spinning. This information is used by the Engine Control Module(ECM) to control ignition and fuel injection. The camshaft position sensor senses the retraction of camshaft (intake) to identify a particular cylinder. The camshaft position sensor senses the piston position. The sensor system consists of a rotating part, typically a disc, as well as a static part, the actual sensor. When the engine is running, the high and low parts of the teeth cause the gap with the sensor to change. The changing gap causes the magnetic field near the sensor to change. The change in the magnetic field cause the voltage from the sensor to change. When the crankshaft position sensor (POS) system becomes inoperative, the camshaft position sensor provides various controls of engine parts instead, utilizing timing of cylinder identification signals.[/QUOTe

Thank you for the information. Is there a diagnostic tool that the garage has that could diagnose it easier?

[Ken Jaworski]

I've always done a physical check on timing marks. Making sure they are lined up by rotating the crankshaft and stopping at the crank timing mark. Then I would look at the camshaft gear timing marks and see how they line up. I would do this three or four times to make sure all the marks continuously line up. If you are off one tooth on the camshaft, you should be able to see it in the marks not lining up exactly.

You may be able to rough check the timing with a compression test as well provided you know the necessary info such as what normal compression for that engine. Say if the normal compression is 150psi and all cylinders are showing 85 psi in a wet condition (oil injected through spark plug hole) then there is a chance the timing is off. The reason I say this is because air may be leaking through an intake or exhaust valve because they are opening or closing late. Say for example on the intake side if the intake valve is still opened while the piston is climbing up the cylinder on its compression stroke, some of the compressed air will escape back through the intake causing a low compression reading. I think you may now see where this is going to possibly indicate the problem. Remember that all cylinders need to show the same low compression readings. If only one or two shows the problem, you have a compression problem maybe in stuck valves or something else. Remember that late or early valve timing will be the same in all cylinders provided they are all relying on the same camshaft. In a DOHC engine one cam handles the intake while the other handles the exhaust.

[petrified.rabbit]

Since you have a p0340 code, that is a circuit code which means you need to check all of the circuit parts for function, including wiring, and ecu function.