E46 M3 Exhaust Cam Shaft Sensor DIY

[Pip]

I stole these steps from a gentleman at m3forum and added my own input. I chose not to remove the strut bar or the engine vanity cover and completed the removal with ease. My body position trick was to straddle the front passenger wheel and sneak one hand between the firewall and the engine finding the sensor bolt and my right hand guiding the business end of the tool to the bolt head. I was using the strut bar as a headrest for ease and relieve some back pain as it is a weird position. At first I used a t30 bit because I thought the smaller tool would help but not sure which one worked better seeing as they both fit.

After getting the position right (hardest part without eyes - reason using one hand to feel/guide is important) it just takes some time to rachet the bolt out. After you've gotten the bolt almost all the way out remember not to drop it. I did drop it but pulled back the heat shield next to the exhaust manifold and used my magnetic tool to retrieve it. I think I was lucky.

Part 17 or 19 is what you'll be changing.



Steps:
1. Remove cabin air filter and box. Also remove the two T30 bolts holding the cabin filter box attached to the firewall for better access to the sensor. See below.



2. 1/4 in ratchet with 5mm short bit





3. Remove the CPS unit from engine - Twist gently and pull

This is the old sensor (new has a grey tip and is bigger). BMW upgraded it but not sure why and people only replace when their sensor is bad. I am replacing the o-ring because I had a leak.



4. Disconnect the CPS sending wire
5. Follow in reverse to install

Recommendations:
1. Allen wrench too hard to use
2. Buy or borrow the 1/4 in ratchet and the 5mm short bit
3. Leave the CPS cable on until the CPS is out of the engine
4. Clean the hole where you took the unit out
5. Add a little clean oil to the new unit and o-ring
6. Add the loctite Blue to the bolt
7. Gentlemen and ladies angle of attack is everything. There is no comfortable positon.

Some recommended changing from the Fillister-head screw to a standard bolt (Case Hardened). 16/32 10 mm head.

[danewilson77]

Thanks!

"No flamesuit required"

[Pip]

One thing to note for those guys with larger hands...get smaller hands. Or do when you're doing a valve adjustment or VCG.

[cakM3]

Thanks for the write up Sean! I will do this when I do the valve guide adjustment over the winter

[Pip]

Thanks for the write up Sean! I will do this when I do the valve guide adjustment over the winter

No problem. I would also do the chain tensioner gasket if you're going to be in there. It is in the front of the engine and I can do a write up for that too. Believe I still have the photos. Let me know if you will need the tools or if you'll be having it done. No sense in you buying anything since I already have.

[Pip]

Alright so had a productive call with BMW parts counter (they didn't have the part near me though). The new sensor is 18.32mm thick where the o-ring sits. The old version is 17.88mm



It was leaking like a sieve with new o-ring so it must have barely been holding on.

[cakM3]

Sean, what's the part number to the new part?

[Pip]

13627796054

[Rovert]

How do you know when you need a new one? Symptoms?

[Pip]

Well if you need a new sensor you'll have a SES code and probably rough idle. Some people mention not having issues other than idle issues. I'm not replacing mine due to issues but because it is causing an oil leak.