2012 Mercedes s550

The fifth generation Mercedes S-Class S500 (or W221), was introduced in 2005 at the Frankfurt International Motor Show. There was a major overhaul in design from the previous generation. The overall dimensions are larger than the previous model, featuring three new additional engine models with a 26% power increase. The 2012 s500 comes with a refreshed interior, and a choice of a column shifter and a center console transmission. The fifth generation was a much needed refresh, adding new styling, advanced technology, an improved interior, safety features, and additional AMG options. 

When we received this s550, the check engine light had come on. As part of our diagnosis, when the vehicle comes in we scan the vehicle for any Diagnostic Trouble Codes (DTC). This vehicle was producing a code for a fault code for the right side intake camshaft actuator solenoid. 

Upon inspection, found oil ingress into the engine wiring harness. Upon a closer inspection of the wiring harness, we found that the oil has migrated to the plug connector on the engine control module. Cross referencing the vehicle Database in Germany, we found that there was a document pertaining to oil in the wiring harness being caused by a defective camshaft solenoids. In order to rectify the problem, the camshaft solenoids, sensors, and engine wiring harness need to be replaced. The most difficult part of the repair is the LIN BUS wire and the wire going to the oil pump. 

The plugs need to be taken apart to enable removal of the wiring harness past the right side of the engine mount. It is very important to take a systematic approach and work from one side at a time, when putting the new harshness in. It is also equally important to route everything back in through the correct sequence and pathing. Any differences can result in pinching of the wiring harness which can cause a short or open circuit code, creating the check engine to become active again. 

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