Camshaft sensor

[MarkG - E85]

Hi again,

Having a few problems lately

My engine light has come on and it's saying it's the camshaft sensor, B position. Basically on the exhaust side, what's the odds on it being just a faulty sensor rather than a more serious problem?

 

[smorris_12]

Depends what the error actually is. If it's a "plausible reading" type code, could be anything. If it's a short to ground/+ve or open circuit, it's the sensor, end of.

 

[colb]

Odds on its a duff sensor quite a common fail on cars of our age, anything else mentioned in the code reading, what scanner was used?

 

[Gwest44]

In my experience once it throws the code its best to replace with new.
My coupe threw the inlet camshaft error code last week and the engine management light came on - the car still drove fine but turned over much longer before firing and ran lumpy for the first couple of minutes
Anyway I'd previously fitted one on a couple of Z3's so I ordered the sensor with intention of swapping it out myself. To my dismay once the sensor arrived I found that replacing the existing one was a much more difficult task than it had been on the Z3.
So I took down to my mechanic but what should have been a relatively quick job turned in to a nightmare when the head of the bolt securing the sensor snapped off. In the end he managed to fabricate a bracket to hold it in until he could take a proper look at it but told me to keep my eye out for any oil leaks from the sensor. Its been fine since and the starting issue has gone along with the EML so fingers crossed the bracket does it's job until its next service is due.

 

[MarkG - E85]

Ok, a quick update. I changed the sensor for a new one but the light still comes on. I bit the bullet and took it to an auto-electrician who immediately said "We won't get involved, we've fallen into the trap of changing sensors before when it wasn't the problem. It will be your vanos unit"

Any advice?

 

[colb]

That's the next move then a Vanos overhaul, trouble with fault codes is that they can lead you in the wrong direction as they have set because of something else having a problem that triggers a code for something related upstream or downstream of the item setting the code.
First move is to take the Vanos solenoid out and clean it, see if that makes a difference.

 

[enuff_zed]

My Autophix 5900 would show live data for the vanos. So you could rev it and watch the angles change.
If yours does the same it will maybe verify the fault.

 

[MarkG - E85]

UPDATE: The BMW specialist has had a look (at a cost of £48) and apparently the B sensor isn't getting a signal from the ECU so it's either the wiring or the ECU itself. They want me to book it in for another 2 hours so they can look a bit deeper to pinpoint the exact fault. If I can find out which block the B sensor is connected to in the ECU, I can test it myself. Does anyone have a wiring diagram of the ECU so I can locate the correct terminals?

 

[MarkG - E85]

Hello again, I've been doing a bit of digging on the net and it seems that the sensor has a fuse located within the ECU itself. But it appears to be for both solenoid valves, the Characteristic Map Cooling Thermostat as well as both camshaft sensors. If this fuse was to blow it would explain why i'm not getting a signal to my B sensor but why am I not seeing any more alarms? I should clarify that my code reader is a really cheap one, could it be the B sensor is the first one coming in and is preventing any further alarms from showing on my reader?

 

[MarkG - E85]

https://www.pelicanparts.com/techarticles/BMW_Z4M/129-ELEC-DME_Replacing/129-ELEC-DME_Replacing.htm

Hope that link works