P0340 - Third sensor

[MazerRackham]

So I just replaced my intake cam sensor with a genuine BMW sensor after going through 2 other generic brands that were also not cheap. After letting the car rip and then letting off throttle I notice it bounce off 500x RPM like she wants to stall. I was under the assumption that with a new cam sensor the improvement would be immediate and the ECU would not have to re-learn if that makes any sense?

The only other thing I can think of at this point is vanos solenoid or something with the MAF. My friend was saying that part of the engine harness could have potentially failed too and that it happened to him. Have any of you experienced this? Would I have to buy an engine harness and then cut and splice the cam sensor pig tail? Is it detachable and separate?

[samy01]

icv maybe?

[JDStrickland]

HOLD THE BUS!

The Check Engine light does not go out by itself. Not entirely true, it does not go out instantly, it has to decide that whatever it thought was wrong before is not still wrong. You can turn the light off and then go through the Readiness Monitor process while the monitors complete the self-test cycles, or you can drive the car until it tests itself enough times that it decides it isn't broken anymore, and the light will then go out.

There are two wires to the sensor, it should be a simple test with a continuity tester (multi meter) to determine the integrity of the wires.

[Eric93se]

I doubt your harness is bad, that is not at all common with these cars. Did you put a new o-ring on the sensor during install? Did you make sure the old o-ring came out of the hole?

After making sensor changes its good to clear the engine adaptations (requires INPA or other) make sure the car has good gas in it.

[JDStrickland]

+1 on the harness, it's not going to fail unless you have critters, and then it would be odd that they only ate the wires to one system component. Any issue with the Check engine (SERVICE ENGINE SOON) Light can be read and cleared with a generic OBD II scan tool. There's no reason not to use INPA, but using INPA is not a requirement.

[spyderg0d]

That code in specific is for the intake cam not at the appropriate angle at certain points in operation of the engine. Yes, a faulty sensor will trigger it ofcoarse. But also include misaligned vanos gear, miss timed camshaft, over stretched timing chain to where the secondary tensioner cannot make up the slack, vanos seals not allowing proper activation of the system, extreme buildup of whatever on the camshaft sensor plate on the camshaft. And there might be a few more possibilities..

[Eric93se]

A bad vanos solenoid that doesn't allow for full oil pressure on the vanos has caused trouble for some.

[JDStrickland]

Wait a minute, he's replacing the sensor and thinking that the light should go off by itself. It can, but not instantly. The timing chain could lift an elevator, it's not gonna stretch. It could, with crappy oil change habits, wear the sprockets to the point where there is lots of slop in the mechanism. But a properly maintained engine will not have a stretched timing chain, and any engine that has a code must have the code reset to turn the light off, or he has to wait until the circuit simply decides that whatever the problem was that it reported has gone away.

[spyderg0d]

The system should recognize the camshaft angle within 2 startups with a good sensor and if its at appropriate angle of coarse. Just like it takes 2 bad starts to set that code if I'm remembering correctly.