Oil Leak Into Wiring Harness From Camshaft Sensor on Mercedes-Benz C230

Problem Description and Possible Solution

Oil can leak into the engine wiring harness from the camshaft sensor. If the leaky sensor is not repaired, the oil can migrate through the wires and possibly damage the engine control unit. Have the sensor and harness checked regularly.

Problem Data
RepairPal Verified
Average mileage: 113,444 (48,000–200,000)
5 model years affected: 1997, 2002, 2003, 2004, more2005
45 people reported this problem
Viewing 1 - 19 of 19 comments
In the shop right now! They are describing this exact situation. I was trying to find the recall notice and found this!
Oil leaking into wiring harness from CAM sensor I am told by my mechanic today. I did find online however that this is a RECALL issue for this car and I am now taking into the Benz Dealer for repair and hope the Engine Check light goes off. This car has run perfectly since day one and really doesn't even appear to be running poorly with the light on. I run it on synthetic Mobil One 5-40 and change it regularly.
I went to dealer for the recall (California) the replaced everything harness computer magnets the car had the same problem camshaft solenoid timing. They charge me 350.00 to see the chain tensioners that were perfect then they wanted to open the chain covers for 2800.00 I told them I didn't trust them, did some work I found they didn't replace the timing sensor intake on left side of the engine I ordered the part one bolt and replaced it, check engine light finally went out.
Went back to dealer and they gave me back the 350.00 they charged me to see the tensioners and the chain.
Don't trust dealers
Dealer is give us the running around. Change the CamShaft solenoid but does not want to change the wiring harness saying its not included in the recall.Anyone has any idea on how to get them to repair this know defect?
Oil leaked on to wire harness. There is a service campaign for this issue: 2009100001.
Mercedes Benz dealership fixed the problem. Material and labor was about $6000. at no cost to me.
Same issue at 80,000 miles on my 04 kompressor. Dealer changed harness adapters but didn't fix underlying cause of the oil. Refuses to help after fix it now or ask MB for help.
noticed a oil leak from camshaft magnetic cover, the oil have found its way into the sensor connector but the engine light nor malfunction messsages have com on. i removed cover (3 screws), cleaned surfaces and applied gasket silicone, put the cover back on, havent started it on to test result. if anyone has the right fix for this i will appreciate if let me know. TY.
oil all over the place, intermittent issues, now car will not crank & will not start.
Found melt/scorch mark under some wires that pass over plastic in engine compartment.
Found another part of wiring harness missing insulation only on the portion passing over a metal section in engine compartment.
Serpentine belt now has what appears to be bubbling or blisters on the surface. Car has had hot or burning plastic smell for too long and dealer/shop attributes it to new parts wearing in. Problem is the smell never ceased!
I am so thoroughly disappointed in what used to be a reputable vehicle manufacturer.
Mercedes Benz is an empty shell of what used to be.
I have a 2005 C230 and I’m having the same issues with it. The check engine light and its running rough, so I googled it and found that there is a common problem with the Camshaft adjusters leaking oil into the wiring harness and causing problems. So I took a look at my car and sure enough the camshaft adjusters are leaking into the wiring harness. I had planned to do the work myself but while searching for parts I discovered that there is a recall Campaign # 2009100001 on the 2004 C230s. So I called the dealer and they said no sir there is not a recall on your vehicle for that issue. So then I emailed Mercies Benz Corporate and explained the same exact thing to them. They replied with this.

Thank you for your email to Mercedes-Benz USA.
A review of the Vehicle Identification Number provided is showing an open service Campaign for the Camshaft Solenoid. When a vehicle is brought into an authorized Mercedes-Benz dealer, they will check the VIN for open recalls and service campaigns (which are VIN specific). It is recommended to bring the vehicle into any authorized Mercedes-Benz dealer. The link below will assist in locating the facility closest to your zip code.

So I doped it off at the dealer and they called me and let me know that the campaign was performed but check engine light and It has a code for a misfire on cylinder 1 and wanted to charge me $400 for a compression check I told them no, I didn't even try and argue with them I call Mercedes-Benz USA Consumer Service direct. And explained to them what was going on and that all of the problems my car is having is historicity caused by the oil leaking in the wiring harness. The Consumer Service rep say that he is passing the iformation on to the Regional Management and that they would contact me within 24hrs.
Camshaft Adjuster On Front of Engine Block leaks oil into the connector. This oil seeps down the wires and into other sensors (Coolant Temp, MAF, ECM/ECU) and can cause drivability and starting issues. Mercedes sells an updated unit and also an updated pigtail wire connector. THIS IS AN EASY FIX compared to replacing ECU so check this connector for oil immediately and often. Replace camshaft adjuster, coolant temp sensor, cam position sensor, thermostat, and cleaned MAF.
Initial problem, Check Engine light. Failing oxygen sensor. MB dealer stated oil in harness. Vehicle not covered by recall for that problem (MB seems to think the cam sensors used on the 2005's are fine). MB dealer wants to replace engine wiring harness and every sensor attached to it, estimate $9,200.
This is the mileage it was at when I noticed that my car had this problem. I replaced the alternator and noticed there was oil all over the wiring down there which is what caused my alternator to go bad as well I believe. I have not had this problem fixed on mine yet, but with it being a recall it should be free to repair I am just trying to figure out where I need to take it for repair?
Same issue as everyone else states cam ssnsor leaking oil into wiring harness and computer needs replaced along with wiring harness, is this an actual recall
In Calif. it's required to get car smog checked every two years, after it's 6-years-old. My 2004 C230 Kompressor runs fine, same performance and gas mileage as when it was new. However the Check Engine Light is always on. A "CEL" is an automatic smog check failure. I can't renew registration, even though my car passes the tailpipe emissions test by a wide margin. The OBD codes (136 & 141) which triggers the CEL indicate a problem with the downstream (i.e. after the catalytic converter) oxygen sensor. Dealer wanted $700+ to replace it. The part costs $109 at AutoZone or Amazon, so I was going to replace it myself. (I've got more time than money, after the company I worked for was sold and I was let go.) I unscrewed the O2 sensor from the exhaust manifold and then when I unplugged the connector at the other end, motor oil poured out. Going online, I learned about this known, common problem: motor oil leaking into the wiring harness. And that sometimes, years after the original warranty expired, Mercedes paid for the repair of this known defect. I called the service writer at the dealer who quoted me $700+ to replace the O2 sensor. He was so excited. He said, "This could be a lot more than $700; it could be thousands!". He refused to check if this known common defect is something Mercedes might pay for. As far as he was concerned, my only option was to bring the car in and authorize a charge of at least $152 for them to tell me what's wrong. Comments anyone?