R1200GS ADV CAM POSITION SENSOR FAULT HELP PLEASE

[RogerJ]

The bike is is an R1200 GS ADV 2007 model, November 2006 production date and 30,000 km. At a routine service the GT-1 diagnosed a "Cam Position Sensor Fault" more specifically that there is no communication with/ or the computer can't read the sensor/ or the cam position sensor is broken.

When the fault was first detected, shorts in the Canbus wiring were found near the multi-connector near the BMS-K and in the harness near where it attaches to the cable of the cam position sensor on the lower right side of the bike. As a temporary measure wire was spliced into these two areas to get me home on a major tour as parts were not then available.

When parts became available the dealer replaced the cable harness to make sure it was not a source of the problem. Also, the cam position sensor itself was swapped out and the pickup itself was carefully examined and checked to make sure it was properly adjusted. The bike still continues to display the "Cam Position Sensor Fault."

They have tried swapping out a BMS-K from another bike and the same fault remains.

Have searched here and it seems that folks have just swapped out the cam position sensor and all was well. Not with mine. They have tried two other cam position sensors and no positive result.

Has anyone had this problem on an R1200 GS and solved it? If so, how was this done? What is causing the condition that results in this fault code? The dealer is still trying to sort this out but I would appreciate the direct experience and wisdom of this board to help with next steps in fixing this condition. Many thanks.

 

[RogerJ]

Just a clarification about the BMS-K "swap" referred to above. When they swapped out the BMS-K they just borrowed another one from a used bike in the shop (i.e. not a NEW one set to my VIN). Might that be why they continued to get the "Cam Position Sensor" error code after swapping out various examples of the sensor? For example, by not having a new BMS-K programmed from Germany to my VIN and then programmed on the GT-1 then it is not possible to get a definitive answer as to what is wrong. Eg. you can not get to the resetting of the adaptation values for every component that has been checked to see that it is/they are operating properly, and, that the BMS-K ITSELF is operating properly. The cam position sensor provides a direct and initial input to the BMS-K. It is possible that my bike's BMS-K contains corrupted information, and, that a borrowed BMS-K from another bike won't allow for a definitive diagnosis of this "cam position sensor" fault? Seems reasonable to me at least that they need to: (1) get a new BMS-K from Germany set to my VIN
(2) Program carefully and properly the BMS-K with the GT-1 (3) Check each component of interest is working properly and reset the adaptation values. Otherwise, corrupt information from my old BMS-K, or the other used swapped BMS-K can obstruct the diagnosis. Not only that it can affect the other components. Just thinking out loud. All constructive input appreciated.

 

[Pukmeister]

It's a strange one this. Surely a replacement cam sensor, loom and BMS-K should cure the fault and the dealer could then clear the fault code held in memory.

Did they state they can't get to the adaptive values with GT-1 and are unable to clear the fault that is resident in memory, or are you speculating??.

Hopefully some electronics specialist on the site may be able to look at the wiring diagram and work it out ??

 

[Deleted account 211025001]

Not exactly the same but the following may help?

I had an EWS (yellow) fault come up on my GS on the morning I was setting off on my first Euro trip, shortly after buying the bike.

I rode it to the dealers and they diagnosed it as a cam position fault. They reckoned it wasn't unheard of as the tolerance allowed was very small and sometimes the sensor got fooled into thinking the cam timing was out when in actuallity it wasn't.

There was no way to 'clear' the record of the fault, nor the EWS warning so they re-loaded the software which did the trick. No problems since.

HTH
Andres

 

[RickG]

I would have thought that provided the new cam position sensor was the right one for your bike and the new wiring is OK, AND if the bike runs as it should with those items fitted then Outtomunch's explanation sounds very plausible to me, ie they simply can't clear the original fault code for some reason. I'm no expert but I don't think the sensors are so clever they can be set up for a specific VIN? No doubt someone will know.

You sure the fault code is the one reporting a sensor fault and not a cam position fault?

 

[RogerJ]

Pukmeister......the tech working on the bike told me he can only get to the point where it calls to input the kilometres and he can't get beyond that in the testing procedure because it would show that the BMS-K is not the right one for the bike in question. Also a friend who is a BMW master tech (not the hands-on wrench in this case) told me that this is not the correct way to proceed to diagnose a fault and that you can not reset the adaptation values which needs to happen when checking any component. This master tech is a diagnosis whiz and I believe what he says about contaminated information staying in the original BMS-K, and complicated further by trying a BMS-K from another bike.

BTW this BMS-K has been in place during a series of electrical problems with this bike over the last 3.5 months. The original wiring loom was replaced as part of a separate problem of "insufficient voltage" arriving at the ABS pump. That loom had a fault in its wires such that only two of the three positives leading to the ABS pump had proper voltage. Something caused a short in the wires such that the loom was damaged and was replaced. When that didn't correct the fault, then a new ABS pump was put in and the fault disappeared. Then came this fault with the Cam Position Sensor. Again, the recently replaced loom had shorts and was spliced. Now, we are working with another new loom and new cam position sensor. All of this is just to say that the original BMS-K has been subject to a lot of electrical shock and diagnostic attempts including hooking in a borrowed BMS-K from another bike. This bike has been worked on in four different BMW Motorrad dealers so has had lots of hands on it with what I would charitably call varying degrees of skill and wisdom.

Andres.....my antenna ring was replaced as part of the recall to the 247 numbered part. One time the bike would not start because the battery had gone bad and that was the only time the EWS light came on (low battery voltage can do that). A new battery was put in and the EWS light has not come on since. Interesting your idea of reloading the software. Might be worth a go (with a fresh BMS-K).

RickG.....it is a cam position sensor fault. I am leaning towards a theory of a slightly battered BMS-K with contaminated information in it that will not allow the fault to be cleared. Of course, as we know, the GT-1 will generate error codes for which there is no explanation in BMW's repertoire of answers.
Also, that a given error may, or may not be directly related to the obvious but be coming from something else as Andres points out. This leaves me and everyone a bit in the dark as to what is causing this.

Thanks for your replies. Please keep them coming. It's enough to drive you to drink.

 

[st247]

Not sure whether this will be of any help but there was a fair discussion on ADVrider about the camshaft sensor - here.

 

[EasySushi]

Pukmeister......the tech working on the bike told me he can only get to the point where it calls to input the kilometres and he can't get beyond that in the testing procedure because it would show that the BMS-K is not the right one for the bike in question. Also a friend who is a BMW master tech (not the hands-on wrench in this case) told me that this is not the correct way to proceed to diagnose a fault and that you can not reset the adaptation values which needs to happen when checking any component. This master tech is a diagnosis whiz and I believe what he says about contaminated information staying in the original BMS-K, and complicated further by trying a BMS-K from another bike.

BTW this BMS-K has been in place during a series of electrical problems with this bike over the last 3.5 months. The original wiring loom was replaced as part of a separate problem of "insufficient voltage" arriving at the ABS pump. That loom had a fault in its wires such that only two of the three positives leading to the ABS pump had proper voltage. Something caused a short in the wires such that the loom was damaged and was replaced. When that didn't correct the fault, then a new ABS pump was put in and the fault disappeared. Then came this fault with the Cam Position Sensor. Again, the recently replaced loom had shorts and was spliced. Now, we are working with another new loom and new cam position sensor. All of this is just to say that the original BMS-K has been subject to a lot of electrical shock and diagnostic attempts including hooking in a borrowed BMS-K from another bike. This bike has been worked on in four different BMW Motorrad dealers so has had lots of hands on it with what I would charitably call varying degrees of skill and wisdom.

Andres.....my antenna ring was replaced as part of the recall to the 247 numbered part. One time the bike would not start because the battery had gone bad and that was the only time the EWS light came on (low battery voltage can do that). A new battery was put in and the EWS light has not come on since. Interesting your idea of reloading the software. Might be worth a go (with a fresh BMS-K).

RickG.....it is a cam position sensor fault. I am leaning towards a theory of a slightly battered BMS-K with contaminated information in it that will not allow the fault to be cleared. Of course, as we know, the GT-1 will generate error codes for which there is no explanation in BMW's repertoire of answers.
Also, that a given error may, or may not be directly related to the obvious but be coming from something else as Andres points out. This leaves me and everyone a bit in the dark as to what is causing this.

Thanks for your replies. Please keep them coming. It's enough to drive you to drink.

Have any of the dealers/techs escalated the problem to BMW, As they don't seem to be getting anywhere. If they are unwilling to do so, it may be worth putting a call to BM yourself


Ty

 

[RogerJ]

St247.....thanks for the link. On the HP2's original complaint, in the end, replacing the sensor did the trick. There were no bad wires going to the component apparently. Interesting read but am still not farther ahead.

EasySushi......yes BMW corporate at higher levels is involved. The bike is in Mexico and Mexico City has provided tips to the dealer's Motorrad Tech (without positive result) and now Munich has provided tips to both which are being tried now. These have included: the harness change, change the cam sensor and its reluctor,change the BMS-K, careful valve adjustment, change the injectors, change the anti-knock sensors.

So far what sticks for me is how you shouldn't use a probably damaged BMS-K to troubleshoot, and, using a borrowed BMSK-K from another bike doesn't work either. Also, as Andres points out, clearing a Cam Position Sensor fault is not easy to do. Sometimes it requires re-installation of the software.

I am willing to bet that a new BMS-K set to my vehicle order file; then properly intialized with the GT-1; re-set the adaptation values, and I am betting the fault will be gone.

All constructive input appreciated.

 

[Pukmeister]

Also, as Andres points out, clearing a Cam Position Sensor fault is not easy to do. Sometimes it requires re-installation of the software.

I am willing to bet that a new BMS-K set to my vehicle order file; then properly intialized with the GT-1; re-set the adaptation values, and I am betting the fault will be gone.

All constructive input appreciated.

Roger, I would agree that the guaranteed solution (as you suggest) is to fit a brand new BMS-K module from the factory and then perform a clean install of the latest operating software. This obviously assumes that the hardware faults (sensor, loom etc) are now rectified and the bike is now fault free. Should your original BMS-K module be free of hardware faults however, a firmware update should be sufficient as Andres states.

The 'firmware' of the bikes operating instructions are burned into the ROM within the relevant module and stay there in the event of power interruptions etc but clearly if you can't get in to the adaptive values held in memory to reset them, you'll never clear the fault code. If the reason you can't access them is because you are using a donor BMS-K unit, why not refit your original BMS-K unit and try a firmware update then try clearing the stored values to see what happens. Worst case you won't fix it and will need a new unit (nothing lost). The fault code(s) must stay resident in memory in the event of power shortages etc, otherwise we could all just disconnect our batteries to clear fault codes.

 

[RogerJ]

Pukmeister....thanks for you input and good summary. At this point not sure I would trust a tech to get the re-programming right. Would have to get the file from Munich with my bike's parameters down onto a computer, create a zip file, transfer it to the GT-1 and to the BMS-K and hope it doesn't hang-up, etc..... After everything that has gone amiss up until now I am thinking more of a keep-it-simple guaranteed solution. Cheers!

 

[MattCero]

Pukmeister....thanks for you input and good summary. At this point not sure I would trust a tech to get the re-programming right. Would have to get the file from Munich with my bike's parameters down onto a computer, create a zip file, transfer it to the GT-1 and to the BMS-K and hope it doesn't hang-up, etc..... After everything that has gone amiss up until now I am thinking more of a keep-it-simple guaranteed solution. Cheers!

Great discussion here. I pulled my Cam position sensor out and it ran the same, very rough and would only stay running if I kept the throttle rolled back some. It would try to idle but nah, it would quickly stall. Pulling the cam pos. sensor made no difference. Question, and only answer if you're positive please, if you pull your cam pos. sensor out, and the engine runs the same, does that mean it's bad? My original situation was that I lost a cylinder coming home the other night, right side. I thought it threw the cam timing but I re-timed both cams, replaced all four plugs, replaced the the two primary coils, confirmed good spray on both injectors and it still will start but I have to keep the throttle engaged for it to run. If I let off the throttle it'll try a little bit to idle but eventually stall. Both pipes are hot after just a little bit so I know there's combustion but what the heck?! Any ideas? Disconnect battery and cross the leads for a bit? I'm at a loss. Thank you.

 

[botus]

Do they even have cam position sensors

or does it really have a crank position sensor - to it know where TDC is for its base ignition reference - CPS' die on cars all day long and often once started the vehicle will run without it - but does tend to stall - they usually wear with heat first becoming temperamental, working when cold and progressively failing with heat - park up, come back and most will run again

As for the very OLD Original Post -was it even programmed to suit the bike - these engine ECUs were even used on the cars - let alone most of the 4 pot bikes - I guess they used old world tools to bodge in the chassis sand immobiliser info in there to make it fire - but on a k1200 map !!!! hahaha

Re your one pot fun - do a compression test ? - they burn out valves regularly at high miles
if that's OK but the bike is running like a pig - I had that with a CAT sensor fail - it deliberately screws the injection on the other pot

 

[Pukmeister]

As Botus says, check or replace the Lambda sensor. I had one fail and it caused dreadful running similar to the symptoms you describe.

 

[Slipperyeel]

Do they even have cam position sensors

or does it really have a crank position sensor - to it know where TDC is for its base ignition reference - CPS' die on cars all day long and often once started the vehicle will run without it - but does tend to stall - they usually wear with heat first becoming temperamental, working when cold and progressively failing with heat - park up, come back and most will run again

As for the very OLD Original Post -was it even programmed to suit the bike - these engine ECUs were even used on the cars - let alone most of the 4 pot bikes - I guess they used old world tools to bodge in the chassis sand immobiliser info in there to make it fire - but on a k1200 map !!!! hahaha

Re your one pot fun - do a compression test ? - they burn out valves regularly at high miles
if that's OK but the bike is running like a pig - I had that with a CAT sensor fail - it deliberately screws the injection on the other pot

On the RH side, with the rocker covers off, you can see the cam sensor (on the TC). Forgot to look on the LH side as had them off to check the valves recently, but I would imagine the same thing is on the LH side also?

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[botus]

On the RH side, with the rocker covers off, you can see the cam sensor (on the TC). Forgot to look on the LH side as had them off to check the valves recently, but I would imagine the same thing is on the LH side also?

that's kind of weird ? https://www.realoem.com/bmw/en/partgrp?id=0307-EUR-07-2007-K25-BMW-R_1200_GS_04_0307,0317_&mg=12

says it has Crank and Cam Pos sensors - but why - usually if you get variable valve timing they need to know where they are (hence u get sensors), the only other reason I can think you'd care was for full on diagnostics - but they can't even be bothered to tell you when the coil sticks are misbehaving - so its unlikely for that.... Strange ?

 

[Slipperyeel]

that's kind of weird ? https://www.realoem.com/bmw/en/partgrp?id=0307-EUR-07-2007-K25-BMW-R_1200_GS_04_0307,0317_&mg=12

says it has Crank and Cam Pos sensors - but why - usually if you get variable valve timing they need to know where they are (hence u get sensors), the only other reason I can think you'd care was for full on diagnostics - but they can't even be bothered to tell you when the coil sticks are misbehaving - so its unlikely for that.... Strange ?

Here's a pic from my recent valve check. LH cylinder. Just above the orange cam chain tensioner blade, you can see the sensor and at 7 o'clock on the cam sprocket, you can see what must be the register to pulse the sensor... I can't think of another explanation for those components...

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[Mistacat]

Crank position sensor tell the ecu when it is at TDC , Cam position sensor tells it which stroke I.e. compression or exhaust , Induction or power.
2 turns of the crank per cycle.

 

[botus]

we didn't have them in the old days...

I guess when the spark was driven off the cam you'd do it via that - but did that mean they'd end up at start missing or doing an extra injection cycle in the hope it was the right one....
...and with the spark no longer mechanically linked to the cam - you need the cam sensor as per Misatcat's post? - which makes me wonder if you could trigger via the knock sensor and throw it away (saving 3 quid per vehicle)?

 

[waggy]

Could this be the TPS sensor causing the symptoms that are being discussed?


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