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Discussion Starter · #1 ·
I got an SES light the other day. At the same time I got a very throaty exhaust at lower RPMs.

So, I took out my Actron CP1945 code reader to scan the codes. After a couple of times trying to establish a connection, it came back with "P0023 Mod$12 1/2 camshaft position Actuator B - Bank 2 circuit malfunction" Aha, the camshaft position sensor. From past posts, I was able to identify that bank 2 is the driver's side for US cars. However, I didn't know which sensor (intake or exhaust) I took a guess and figured that since the exhaust note changed, it would most likely be the exhaust sensor. (Is this a valid assumption?)

So I purchased the exhaust sensor, and went about replacing it. The procedure outlined in TIS seems benign enough, there are only 4 steps. However, as others have found, this task is nearly impossible on the drivers side due to the lack off access once you remove the air duct for the cabin filter. I somehow managed to replace the sensor (dropping my allen wrench a couple of times into the bottom recesses of the engine compartment) One hint I can provide for any future DIYers is to use a shoptowel to cover the hoseclamps going to the heat exchanger so that you don't scratch up your hands performing the repair.

Next step was resetting the SES light, which is a function the Actron unit provides. However, it took me about 10 times to try and establish a connection with the car. This is very typical of this tool. My wife's MDX has no problem establishing a connection every time, but any BMW I have tried this tool on has always been a real pain to establish a connection with. After finally establishing a connection I was able to clear the SES light. Phew, I thought I was done. As I was patting myself on the back for a job well done, ...

I decided to take a drive to confirm my repair and also allow the engine some time to reset the adaptive data. When I started the car, all was normal. As I started to drive however, the throaty exhaust note was still there and after 5 mins, I got another SES light.

So back home I came to re-read the codes. Of course, I could not establish another connection with the reader despite having tried I don't know how many times. Grrr. So I went online last night and finally resigned myself to purchase the Peake reader. While that is being shipped to me, I'm left wondering where I went wrong...

- Is it possible that I should have replaced the intake sensor?
- Is it possible that bank 2 is not the drivers side on a US car?
- Will the peake tool provide more feedback as to what specific sensor is faulty?
- Is it possible the code was thrown for an entirely different problem?
- If it is the intake sensor on the drivers side, how in the world can this one be changed without taking out the engine? :)
 

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verhagke said:
I got an SES light the other day. At the same time I got a very throaty exhaust at lower RPMs.

- Is it possible that I should have replaced the intake sensor?
- Is it possible that bank 2 is not the drivers side on a US car?
- Will the peake tool provide more feedback as to what specific sensor is faulty?
- Is it possible the code was thrown for an entirely different problem?
- If it is the intake sensor on the drivers side, how in the world can this one be changed without taking out the engine? :)
Can only help on location. Bank 2 is drivers side in US.
Regards,
Jerry
 

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I have had this code set and engine sound twice, both times was fixed with the exhaust sensor, drivers side. This is the outboard sensor, points down. Forget the book, easy to replace from underneath the car!

Infant mortality on new sensor or improper install likely...

Cheers

Mike
 

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verhagke said:
- Is it possible that I should have replaced the intake sensor?
Yes. The blatty exhaust note is overlap, from a retarded intake cam. I think what happens is that when the DME can't detect what position the cam is in it goes into a 'fail-safe' position.

- Will the peake tool provide more feedback as to what specific sensor is faulty?
Yes, the R5/FCX-II will tell you which bank and cam.

- Is it possible the code was thrown for an entirely different problem?
VANOS failure, I guess. Mine had a failure under warranty and they replaced a bunch of stuff. I got the blatty-exhaust again about four months ago, bought a Peake, said bank 1 intake, I ignored it for a while and after cycling in and out of blatty-mode a few times over the next week it went away and has stayed away for the last three months. Transient VANOS problem?

- If it is the intake sensor on the drivers side, how in the world can this one be changed without taking out the engine? :)
From under the car. Still a *****, but doable. Sounds to me like you need the BMW TIS CD ;)
 

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Discussion Starter · #5 ·
JEM said:
Yes. The blatty exhaust note is overlap, from a retarded intake cam. I think what happens is that when the DME can't detect what position the cam is in it goes into a 'fail-safe' position.



Yes, the R5/FCX-II will tell you which bank and cam.



VANOS failure, I guess. Mine had a failure under warranty and they replaced a bunch of stuff. I got the blatty-exhaust again about four months ago, bought a Peake, said bank 1 intake, I ignored it for a while and after cycling in and out of blatty-mode a few times over the next week it went away and has stayed away for the last three months. Transient VANOS problem?



From under the car. Still a *****, but doable. Sounds to me like you need the BMW TIS CD ;)
I think you may be on to something. The VANOS going into safe mode makes sense and this would obviously affect both intake and exhaust valves. While I am still waiting to receive the Peake tool, (hasn't even shipped yet) I will purchase a new intake sensor today so that I can replace it over the weekend. Can't hurt and if I didn't need to replace it, I'll then have a spare. I'm crossing my fingers that I don't have any issues with the VANOS itself.

I will definitely try to get to it from under the car.

I miss driving my beast!!!
 

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Discussion Starter · #6 ·
Well, I got the peake reader. Code which comes back is "Exhaust camshaft VANOS position control cyl #5-8" This means that the original diagnosis using my Actron scanner was incorrect.

Researched the repair for that and found that the solenoid valves on the drivers side have likely failed. I found instructions on TIS (#11 36 640) for the repair. Looks pretty straightforward. Anyone done this themselves? Any words of wisdom?
 

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Discussion Starter · #7 · (Edited)
I replaced the left bank VANOS solenoid valves and what a difference! Car is much more responsive. I also disconnected the battery for a while to reset the adaptive settings.

I purchased the parts from Pacific BMW for $300. The part includes 4 solenoids and a circuit board already assembled. I have been told I could have just bought one of the solenoids, but I would have had to do some soldering to replace it. Much easier to just buy the whole thing.

It turned out to be a very straightforward DIY:
- pop the hooks which keep on the airfilter cover using a large flathead screwdriver.

- loosen the hose clamp which connects the air intake hose to the plenum cover

- rotate the airfilter cover upwards at the plenum cover until its pointing straight up and out of the way.

- cover the airfilter and plug the intake on the air intake hose with clean shop towels.

- the solenoid valve cover is located directly behind the main radiator hose. This hose does not have to be removed since it's quite flexible and can easily be compressed to gain access.

- the solenoid valve cover is held on with 5 hex bolts (6mm). There are an additional 4 hex bolts (also 6mm) in the cover which hold each solenoid in place inside the cover. (cars before MY2000 do not have these 4 additional bolts)

- Remove the 4 tensioner bolts first. These were a bit difficult to release. I had to use a breaker bar to remove them. Keep them as they can be reused.

- Remove the 5 hex bolts holding the cover on. These came off quite easily.

- pull the cover off, and remove the old gasket.

- disconnect the electrical connector.

- using pliers covered with a towel, pull out the 4 solenoids one at a time. The whole circuit board with the 4 solenoids comes out. The 4 holes will drip some oil. so put a shop towel underneath them to catch it. Clean out any oil from the area where the circuit board sits. Make sure you don't get anything (dirt) into the solenoid openings on the VANOs unit.

- lubricate the new solenoids and it's O-rings with fresh oil.

- Push the new solenoids back into position in the same orientation. Use your thumb to push them all the way in. They sort of snap into place.

- put the new gasket in place.

- Place the wire grommet into the cover and place the cover back on the solenoid bank. This was the most difficult part of the job as there isn't a lot of access and the wire will want to twist the grommet out.

- replace the 5 bolts which hold down the cover, and torque them down as mentioned to torque spec in 11 36 640. (Sorry, don't have TIS running just now)

- replace the 4 tension bolts and torque them down to the proper torque specs.

- pull the shop towels from the air intake and twist the air intake back down.

- snap the locks into place and tighten the hose clamp to finish the job.

All in all, it took about 1.5 hours. Sorry I didn't get any pictures while doing the work, but I hope that the following diagram may provide some help:

http://www.realoem.com/bmw/showparts.do?model=DE93&mospid=47592&btnr=11_2674&hg=11&fg=15

item 2 is the solenoid valve assembly and item 7 is the new gasket you'll need
 

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verhagke said:
All in all, it took about 1.5 hours. Sorry I didn't get any pictures while doing the work, but I hope that the following diagram may provide some help:
Y'know, I like finding out that the scary-sounding jobs (oooh, VANOS...) are easier than changing a power-steering hose on a Saab 9000.
 
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