It may not be your sensor. You can try it first but if code persists, it could be chain tensioner or variable timing cam, a common issue with pre 2014s.

 

Thanks for replying, Cmitch

Yeah, I figured as much. Chains, sprockets, adjusters/actuators... those are all out of my comfort zone with car repairs, so if this doesn't work, the car will go to the dealership. Do you happen to know if those items that I highlighted on the images are indeed camshaft sensors?

 

Yes, what you circled are 2 of the 4 camshaft HALL sensors. You also have 4 camshaft solenoids, which are larger and located on the cylinder head front covers.

You might have a bad sensor, but those rarely fail. What is much more common, is oil in the engine wiring harness and engine control module. Oil comes through those camshaft hall sensors and enters into the harness, which makes its way up to the engine control module, and causes all sorts of weird stuff.

To replace the cam hall sensors, the intake manifold needs to be removed. The sensor under the air filter box is the easiest one to get to, remove the air filter box and disconnect the hall sensor. Check the connection for oil.

 

Yes, what you circled are 2 of the 4 camshaft HALL sensors. You also have 4 camshaft solenoids, which are larger and located on the cylinder head front covers.

You might have a bad sensor, but those rarely fail. What is much more common, is oil in the engine wiring harness and engine control module. Oil comes through those camshaft hall sensors and enters into the harness, which makes its way up to the engine consetrol module, and causes all sorts of weird stuff.
2
To replace the cam hall sensors, the intake manifold needs to be removed. The sensor under the air filter box is the ea kansiest one to get to, remove the air filter box annsd disconnect the hall sensor. Check the connection for oil.

Ah, okay. Good point about the oil traveling through the sensors and potentially wreaking havoc in the engine wiring harness. I didn't know there were 4 camshaft sensors. I'll remove the intake manifold, find the other bank 2 camshaft sensor this weekend and check for oil in the connectors.

Thanks for the advice!

 

I do not recommend removing the intake manifold. Unless you done that before, and are comfortable with it.

All you need to do is remove the air filter box and you can access that cam hall sensor for inspection. Then disconnect both engine control module connectors and inspect for oil. It is possible to get to one other cam sensor without removing the intake, but it's very tight to remove the connector.

 

I do not recommend removing the intake manifold. Unless you done that before, and are comfortable with it.

All you need to do is remove the air filter box and you can access that cam hall sensor for inspection. Then disconnect both engine control module connectors and inspect for oil. It is possible to get to one other cam sensor without removing the intake, but it's very tight to remove the connector.

I’ve removed the intake manifold before when checking my spark plugs but if I don’t have to, that’s obviously more ideal. I’ll try the air filter box route first.

 

Sorry to bring an old topic up but I'm having the same issue/code. Car actually makes a horrible noise like something rattling on cold start but goes away within 1-2 seconds.. did you ever find your solution?

I’m having the same exact issue on my wife’s 2014 ML350

 

Did you ever find out what it was?

 

I am having the exact same issue , after reading several posts , in summary the recommended path of action is as follows:
OBDII display - P0346, camshaft position sensor A circuit range/performance Bank 2 ,
1. confirm which sensor
2. confirm for oil leaks in wiring and ECM
3. replace sensor opposite cylinder 1
4. OE# part # 276-905-1000 for sensor
5. if problem persists - explore chain tensioner and variable timing CAM
please advise if someone has additional guidance

 

Do you have pics of the exact location of the sensor

 

Hello forum members- would appreciate any feedback/observations on this topic -

 

Same issue. I'm new here, should this be bumped to a separate post?

 

Do you have pics of exactly where the sonsor is

 

i can see the 4 sensors , if you are standing in front of the car the left is Bank 1 and the sensor A ( intake) and Sensor B ( exhaust ) are visible next to the magnet sensor, on the right side ( Bank 2) the A ( suction) sensor is on top and right below the black cover plate, sensor B is to the right of it also hidden under the black cover plate

 

there are 4 sensors on the engine to my knowledge , please see the very 1st post in this thread for the locations. i am just wondering if other people have had this issue and what they did, am leaning towards replacing all 4 sensors ( $65/pc OEM part) and see if the issue goes away. thanks

 

Hey I'm having this same exact issue with code p0346 on my c300, did you fix this issue and if so what was it and dealership cost?

 

the check engine light comes on then goes off by itself, there is no other indication or impact to driving the car. I will be taking it in this week for another check and will post results, i might just change all 4 sensors and see if the alarm goes away .

 

update - after 3 months of research, watching all you tube videos, reading the Benzworld blog, consulting 3 different Euro car shops for detailed diagnosis- here is the outcome
1. replaced all 4 sensors, with MB original parts , car continued to rattle on cold start and had a few seconds lag before stating up, specially when cold , after start up car ran fine
2. One mechanic after doing diagnostics , correctly said that camshaft adjuster, tensioner, camshaft ( bank2) need to be replaced, using all MB OEM parts, the care was fixed and is now running fine
3. 2 other mechanics were recommending replacing the timing chain, timing chain tensioner, timing chain guide , and sprocket, for both Bank 1 and 2, which was the wrong recommendation , non of that work was needed to fix the car.
4. most of my research has indicated that this is a typical problem with the M276 and if caught and fixed as soon as the rattling noise appears one can get away with just replacing the sprocket and not the camshaft.

 

How much did that fix cost you in parts and labor?

 

i got quotes anywhere from $10,000 to $4500 , using certified Euro car mechanics. the thing to watch out for is that once you agree to replace the timing chain, tensioner etc and the valve cover is opened , and camshaft issues are visible the cost to repair will also most double. It is critical to get the scope of work 100% correct prior to opening the car and agreeing on a scope.