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A P0015 code started last month on my 2007 S550. After one reset with my OBDII scanner, the CEL came back after a week. Not wanting to have this get worse, did some research and found the following which prompted me to jump on this DIY repair for an original solenoid magnet that should be replaced with an upgrade.

Purpose
The camshaft sensor is magnetic device with a solenoid. It gathers and sends information about the car’s camshaft speed (and as a result the position of each piston) to the electronic control module. This information is received by the computer, which then uses this data to further calculate the time of ignition and the timing of fuel injection required by the engine. Progressive problems with these sensors are:

1. "Check Engine" Light
The first symptom of a failing camshaft sensor manifests as a warning from the car’s control module. As the camshaft sensor fails, the computer sends the driver a warning sign via the “check engine” light on the car’s dashboard. When the check engine light first comes on, the driver has enough time to service the car and replace all faulty parts, including the failing camshaft sensor. However, if you ignore this flashing light for a considerable time, it could later lead to engine trouble.

2. Disrupted Driving
Another symptom of a failing camshaft sensor is experiencing constant disruption while driving. If you are experiencing symptoms like frequent stalling, poor idling of the car at 500 to 600 rpms, a massive drop in the rpms slowing down the car to a crawl, a noticeable drop in engine power, poor mileage, abnormal acceleration activity, frequent stumbling, etc., it probably means you have a failing camshaft sensor that needs immediate attention.

3. Ignition Trouble
If you ignore all of the above symptoms, you end up with one that really can’t be ignored—no ignition. Remember, as the sensor begins to weaken, so does the signal it transmits to the car’s computerized control station. If you let the problem carry on for too long, the engine will suffer from a “no spark” situation. Once the signal switches off, so will your engine, thereby stranding you.

 

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Troubleshooting

For my condition, P0015 code is Bank 1 Position "B" for the Camshaft Position Sensor. (Not to be confused with the single Crankshaft Position Sensor which detects the flywheel and crankshaft position). Bank 1 is passenger side of engine, and position "B" is the exhaust cam. So I needed to replace the solenoid on the exhaust cam on the passenger's side of the engine. The top one is the Intake and the bottom is the Exhaust. As a preventive measure, I replaced both solenoids. The M272 and M273 engines have four camshaft positions sensors and solenoids, so other CEL similar codes may be p0011, p0012, and P0014.

Found a STAR diagnostic screen which indicates Solenoid Magnet replacement is part# A2720510177 as opposed to doing the hall-effect sensor replacement for M272 engine (STAR also indicates not to replace the hall-effect sensor). My S550 is a 2007 5,461 cc (5.461 L; 333.3 cu in) V8 (M273) engine. However, the M272 and M273 are modular cousins, and the M272 is just the 6 cylinder version. These parts and instructions should compatible between all MB platforms that use these two engines.

I got new MB camshaft solenoid magnets from FCPEuro for about $25 each. The Solenoid Magnet replacement is part# A2720510177. (See Picture) Evidently, this is an upgrade part from original A2720510 0 77 which proves to be a bit wonky over time.

 

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Location

Attached is the EPC diagram of where these components are located. Also attached is a pdf pic of the front of the engine cylinder heads of where the solenoids/magnets are with a clean / new assembly.

These magnets (and the sensors, if necessary) are easier to replace on the Bank 1 (passenger side). However, to get to the three torx bolts and replace these solenoid magnets on the Driver’s side, you may have to remove the oil cooler (for one solenoid magnet) and remove the PS fluid reservoir (for the other solenoid magnet). (See picture of Bank 2 locations) For now, I replaced both the solenoid magnets on the passenger side, because they are easily accessible and that’s the side giving me the CEL.

 

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Tools and supplies

A list of tools / supplies that should be on hand if you tackle this DIY.

E8 (external torx socket)
Ratchet with extensions
Small flat bladed Screwdriver,
Tool pickup magnet
Magnetic tray to hold screws and bolts
8mm socket with ratchet to remove the bottom engine air dams
Thread locker - Locktite Blue
Nitrile gloves
Lamp

 

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Removal and Reinstallation

To get to the three T8 torx bolts in the intake solenoid on the Bank 1, you will first have to remove at least 2 of the bolts for the bracket that holds the MOT and front engine cover. On the exhaust side, remove the one bolt holding the engine oil dipstick bracket and secure the dipstick tube to the side. Taking these steps will allow straight access to the three T8 torx bolts on each of the solenoid magnets.

Then remove the 3 bolts in each solenoid with an E8 external torx socket, using the magnet tool to keep from dropping the bolts. [If a bolt drops, you will have to remove the under engine plastic covers to fish out the dropped item.]

Pull the solenoid magnet straight out from the engine (may need to start with a pry using a screwdriver). Pull the solenoid out. (Pic) Then use the flat end of the screw driver to push up the grey electrical locking tab about 3 mm. (Pic) Next, place the flat end of the screw driver between the solenoid electrical socket and the wiring harness to release the final catch on the plug. (Pic) Pull apart.

Use a bit of engine oil on the o-ring of the new solenoid. Reattached the electrical connector. Push down on the grey locking tab for the connector. Reset the solenoid into the engine head.

Place a small amount of threadlocker on the torx bolts and reinstall each bolt by starting / holding with the magnet tool. (pic) I did not know the torque value so wrench tighten snugly - letting the thread locker do its thing. Restore the brackets that were previously removed.

 

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Post Maintenance test and CEL reset

STAR Diagnostic Post replacement – or Reset CEL with an OBD2 scanner.

Alternatively, drive vehicle in 2nd gear with cold engine. Increase / reduce speed by 40%.

Cheers