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Replacing the left-hand side intake camshaft position sensor on E39 M5 S62B50.
Symptoms:
Very unstable idle, rattling sounds, poor torque (especially at low RPMs).
Checked OBD fault-codes and found P0345 Camshaft position sensor Cylinder 5-8 bank 2 Intake.
(Peak code table 18 code 08 should be the equivalent, I think.)
Oh no, that is the left-hand side (US driver´s side) (cylinder bank 2, cylinders 5-8) intake camshaft position sensor, which is supposed to be extremely difficult to change yourself.
Well, it is. Here is how we did it. (Or actually, how we would do it if we ever have to do it again…)
By using this procedure you agree to assume the full risks arising from following this proceure. I shall not be held liable for any damage direct or indirect arising from using this procedure. The description of the procedure is a historical record of how I and my GF replaced the sensor. It is provided for your amusement. Like any other historical record, following it may not be the optimal thing to do, and following it may not lead to the desired result.
I strongly suggest not to attempt this alone. Having another person around to help reach in the really tight places, and to holding things and as a moral support is very useful.
If the other person has small hands, it will help a lot, especially when it comes to loosening the screws, and when it comes to reassembly of the bracket.
When it comes to me, I am certain I would not have managed this on my own.
If you get stuck, take a break. Relax, tidy up the work place, wash your hands, have a snack and think things through. Rest yourself, and then try again. Do not use excessive force.
Changing the left hand side intake camshaft position sensor (aka CPS) would have been a very easy job if it were not for three hoses with engine coolant going to the passenger compartment heater. These hoses pass through the bulkhead at the exactly wrong place from a CPS replacement standpoint.
To make the job easy I think there are three options:
1. Drain engine coolant and remove the hoses. (and make sure to get it properly watertight against pressurized hot engine coolant afterwards)
2. Pull the engine and voilá, the CPS replacment becomes a very easy engine-out job.
3. Get smaller hands, and a mirror inspection tool.
I used method three. A word of caution. You will hurt yourself during this DIY. You will cut yourself, and you will bruise yourself, and your back will hurt, and probably your knees and legs too from leaning forward against the car for a number of hours.
I suggest to plan for this to take a whole day, and take frequent brakes doing other things inbetween, before losing your patience, concentration, spirit, humor or temper.
This is not something you want to do when under time-pressure. You need to take it slow and easy. I´m not joking, due to the extremely confined work area, and a lot of sharp stuff in the wrong places, it takes more time and more pain than you would imagine from the work description.
There is also a serious risk of wound infection, so when you inevitably do cut yourself, take time out to clean the wound properly and cover with band aid. If you do not understand the medical risks involved from even small wounds, do not attempt this DIY procedure, instead leave the job to a professional auto mechanic with proper BMW training and experience.
Parts needed:
1. Intake camshaft sensor BMW P/N 12 14 7 539 173
(To the right is the new BMW part. It replaces 12 14 1 438 082 (to the left) which looks a bit different. If your car has the old part, don´t worry, the new part will fit although it looks as if it would not.)
2. Gasket 17x3 mm BMW P/N 12 14 1 748 398
3. Small quantity of engine oil for lubricating gasket.
Tools you will need:
¼” square ratchet
¼” 10mm socket
¼” short extender
¼” sqare to ¼” hexagonal bit adapter
5mm allen bit
5mm allen key with long shaft
small ¼” hexagonal bit ratchet driver, such as Teng Tools 1400 B
¼” hexagonal to ¼” square adapter (to attach a socket to the hexagonal bit ratchet driver)
Stubby (very short) screwdriver with a wide flat blade
small mirror inspection tool with built-in lamp
Magnetic pick-up tool (for when you drop something)
1 pair of woman hands (glove size 6 or smaller)
Band-Aid (I used 4, and GF used 2 or 3, I think…)
You may also find a small magnetic tray useful for keeping all the small tools and hardware in place.
The procedure:
1. Make sure the engine is cold enough to be comfortable to work with. Leaving the car to cool down overnight is a good idea. Forget using gloves for this job. You will need all the tactile info you can get.
2. Remove the left-side passenger air duct clamp. There are three locking devices on the top. Then push the clamp down to release the underside from the passenger air filter.
3. Twist the air duct upwards to release it from the bulkhead.
4. Remove the left-side passenger air filter locking clamp
the air filter lid
and the air filter bottom
Before removing the air filter bottom, pay close attention to how it fits to the surrounding plastic parts, and to the drain.
5. Find the location of the bank 2 intake camshaft position sensor.
The sensor is located near the rear end of the camshaft. The camshaft is most easily located by looking at the left-side Vanos unit. The intake camshaft is located at the center of the part of the vanos that is towards the center of the engine.
Then imagine a line going backwards to the other end of the engine. That is where the intake CPS is.
6. The intake CPS is behind a metal bracket.
7. Look around the area with the mirror to familiarize yourself. Feel around the metal bracket to learn to navigate the area using touch only.
You need to spend enough time doing this to get a really good spatial and tactile understanding of the area.
8. Find the two 10mm hexagonal head screws holding the metal bracket. These screws also hold another metal bracket that is holding the fuel lines.
9. Loosen the screws using the abovementioned tools. You will need to assemble a 10mm socket and driver combination that fits between the engine and the coolant hoses.
10. Do not remove the screws until both screws are loosened. (If you can not loosen both screws, you will need to retighten the screws and let the pros have a go at the job)
11. Remove spark-plug cover. There are two 10mm nuts holding it in place. The nuts have a washer and a rubber gasket each. Those will often be stuck to the nuts, or may come apart.
12. Once the 10mm nuts are removed, pull the spark-plug cover away from the engine as far as the tubing wil allow, then gently wriggle it forward-outward to remove it from the engine. No force is needed, just careful wriggling to ease it clear of the tubing and Vanos unit.
13. Look at the gasket that is located around the periphery of the spark-plug well, and look at the rubber boot that surrounds the spark-plug-coil-wires. You will need to get these in place later.
14. Pull on the metal locking bracket for the cylinder 5 (the rearmost cylinder of bank 2) ignition coil connector. This will eject the connector into the rubber boot.
15. Pull rubber boot upwards-outwards to release it from the spark-plug well.
16. Locate the plastic box at the rear of the engine into which the ignition cables run.
17. Remove knock sensor connector from the plastic box. (picture) This connector simply pulls out of its friction lock.
18. Use the mirror to locate the two metal posts protruding from the metal bracket. Take the stubby screwdriver with the wide flat blade and use it to carefully pry the plastic box loose from the metal posts of the bracket.
Alternately pry near each of the posts until the plastic box comes loose.
19. Remove the (10mm head) screws you previously loosened.
20. Remove the metal bracket.
21. Remove the intake CPS connector. It has two locking tabs located vertically on the top and bottom of the connector. Push the tabs towards each other while pulling on the connector.
22. Use the allen key to loosen the screw holding the sensor.
23. Use the bit racket to unscrew the screw.
24. Twist on the sensor to loosen it. Then twist and pull to slowly remove it from the engine.
25. There is a gasket around the sensor. The gasket may follow the sensor or it may remain in the engine. If it does not follow the sensor you will need to check with the mirror that it is properly in place.
If the gasket does not look OK you need to replace it. If so, remove the old gasket. Put a small amount of new engine oil onto the new gasket and put it onto the sensor.
26. Insert and twist new sensor in place.
27. Align hole (check with mirror) and insert and gently tighten the allen head screw.
28. Attach connector to the CPS.
29. Insert metal bracket. It goes between the bottom of the fuel line bracket and the engine.
30. Insert one of the screws, and turn it a little into the engine.
31. Insert the other screw. Tighten both screws.
32. Align plastic box with the tabs protruding from the metal bracket. Use mirror to check alignment. Gently push box in place.
33. Insert the knock sensor connector.
34. Put the ignition coil connector in place.
35. Put the rubber boot in place.
36. Put the spark plug well gasket in place.
37. Put the spark plug well cover in place.
38. Put the nuts in place, and tighten.
39. Put the passenger compartment air filter in place. Put the lid in place.
40. Put the locking clamp in place.
41. Put the bonnet (engine hood) switch connector in place.
42. Put the passenger compartment air duct in place. This takes patience and gentle force. Too much of the latter and the plastic nabs that secure the air duct bayonet to the bulkhead will break.
David
Replacing the left-hand side intake camshaft position sensor on E39 M5 S62B50
I used your great write-up to tackle both the intake and exhaust CPS on bank 2 last Sunday. The SES light is now off and she's running great once again. 
Linear Mode
