I've been slacking for way too long. Here are the instructions on replacing the intake camshaft position sensor (problem discussed earlier in this thread
- I'm not a mechanic, nor will I ever be. Follow these directions at your own risk!!
First, the problem
The SES light was off and on for a few weeks. There were a number of different faults being thrown. I also noticed that occassionally, a deep low rumble would appear almost sounded like I had a hole in my muffler. After resetting the lights a few times, and trying to debug the problem I noticed that only two errors were constantly being thrown, MAFS fault and camshaft
position sensor (CPS) fault (with the CPS errors being thrown first). Since the CPS error was listed first and cheaper, I decided to replace this first. The error reported that intake CPS for cylinders 1-4 was possibly faulty.
* Intake CPS (also called a pulse generator) - Costs around ~$80 USD (dependent on where you buy it and various discounts; e.g. - CCA).
* O-ring - $1-2 USD
* Flat head screwdriver - medium size
* 5 mm allen wrench - I'm fairly certain this is the correct size
* Bright light!
* Small hands preferred
* Roughly 30 minutes. I could probably do it in 15 minutes after running through it once. Leave yourself one hour just in case. Make sure you understand what to do before doing it!!
The following directions are provided for removing the intake CPS for Cylinders 1-4 (left side of engine when facing the front of the car). If you need to replace the intake CPS for Cylinders 5-8, the instructions will be the same.
Step 1 - Removal of the Airduct
In order to gain access to the intake CPS, you'll need to remove the airduct which connects the airfilter to the firewall. It's located at the top of the engine bay on your left hand side. Unfortunately, I don't have a nice pic with an arrow pointing to it.
First, you'll need to unhook five tabs connecting the airduct to the air filter box. There are three tabs on top (see three horizontal arrows in picture attached) and two underneath. Gently use your flat head screwdriver to pry them off. Once all five tabs are free you are ready to remove the airduct.
Using one hand grab the airduct near the base where it is connected to the firewall. Use your other hand to steady the rest of the duct. GENTLY
twist/swivle the air duct upwards so that the part of the airduct connected to the air filter box is pointed upwards (The TIS instructions caution that using excess force could damage the firewall... bad thing to do!).
Once it's pointed, upwards, you should be able to easily pull the airduct out. Experience has shown that that removal of the airduct is much easier than putting it back in!!
Picture of airduct removed... the set of three yellow arrows on the right show the little tabs that are used to keep the airduct in place.
This picture is a closeup of the airduct and you can see how it is connected to the firewall. So removing it requires twisting and pull out towards you.
Step 2 - Locating the intake CPS
Once you've removed the airduct you'll need to find the intake CPS. The picture below aids in it's location.
Step 3 - Removing the connector
Here is are two pictures of the intake CPS removed. The 1st picture show how the CPS is oriented in the car (the screw is at the highest point). The second picture shows the bottom portion of the sensor and the old O-ring. The plug you need to remove is simply connected via a tab. Disconnect this first.
Once disconnected, you can unscrew the single bolt (5mm allen wrench) used to keep the sensor in place.
Step 4 - Install new intake CPS
The BMW TIS instructions stated that you should first screw in the new intake CPS first but I found it easier to connect the plug first and then screw the intake CPS in place. Do what you feel is comfortable...
Step 5 - Putting airduct back in place
Once you've got the CPS sensor in place and the connector attached, it's time to put the airduct back in place. This is the trickiest part of the whole process. I recommend studying the tabs on the firewall and slots in the airduct (see above pics) a bit. Once you've understood how it fits, putting it back in is just a matter of patience. When everything lines up, it should easily twist back into place. I found that I needed to push the airduct in and
turn the duct back down to get it locked in place. Again... be GENTLE. Don't force the airduct to snap in... you don't want to break any thing.
Once the airduct has been locked in place to the firewall. Reattached the five tabs to the airduct. It should be fairly easy to lock each in place. If you got quite a bit of distance, then the airduct was probably not put back in correctly.
Step 6 - Test drive
When I test drove the car for the first time, it ran REALLY rough; lots of hesitation and such. I thought I had just trashed my car.
I pulled over and waited a minute or so. After that no more hesitation and everything ran perfectly. You probably need to let it run idle for a couple minutes. SES lights never returned and I never saw the camshaft position sensor error again!
- Replacing the intake CPS for cylinders 5-8 is a bit more difficult since there is not a clear path to the sensor. I'd recommend removing the right side airduct first and taking a look for yourself. If it's too difficult to reach then procedures are pretty much identical.
I've never written once of these TECH instructions before... if anything is confusing let me know and I'll try and clarify.