adnan khandakar

Guys need help!!!
Engine chk bulb came up all of a sudden and took a bit more time ( long self ) to start

Plutoe

Clear the fault! If returns replace the sensor!

adnan khandakar

which sensors to be changed?

KEY08

The crankshaft position sensor. Mine failed on my W211 and no issues with either of my W212's so far. The part is cheap

Sreekanth SR

Hi...after replacing crankshaft sensor is ur complaint resolved. I too have the same issue, I have replaced intake cam sensor and crank sensor but still the same complaint persists. So I have tried for a time chain replacement along with VVT, still the same issue is there. Wiring for all sensors and solenoids are ok. Even I have removed engine for inspecting crank sensor rotor. All these seems to be perfect. We have fixed the timings twice since the complaint was showing there is a mismatch between cam and crank. Is there any solution for this.

Expecting replies from others too

Mud

Suggest checking wiring harness and connectors when fault codes repeat.

Sreekanth SR

Wirings and couplers are perfect, even I have disconnected each couplers of cam sensor, cam solenoids and crank sensor. All these times the trouble code is shown as open circuit. Sensors and solenoids have been swapped as well. Still the same fault persists. Seeking advice

cluck

Hi Adnan were you able to sort out the problem for this fault code. I have a 2014 c200 with same fault and have tried replacing timing chain, cam gears, swapped cam solenoids & sensors, checked wiring and have had no luck. Was hoping you might have sorted and able to help me. Would appreciate any feedback . Thanks

Rickman30

I'm wondering if the reluctor wheel on the camshaft itself has shifted. The M276 and 278 camshafts seem to have some issues with the reluctor being pressed on and not tack welded. One person repositioned the reluctor and tack welded to prevent movement again.

Don't know if this helps, but hopefully give a different approach to the concern.

CaliBenzDriver

Rick, that sounds right. Following is a free fix if factory marks are visible.

Have a look at this .


++++++
I believe the loose cam sensor wheel sliding around is caused by VVT jerking impacts.

What helps that happen is the faulty phaser lock-pin no longer holding automatically during low oil pressure conditions.

We know the missing tensioner check-valve help make the tensioners limp in regard to raming by valves.
The loose chains provide camshafts freedom to rock loosely during low oil pressure conditions.

Low oil pressure is available during startup when hydraulic phasers are empty as well as non-ratcheting tensioners.

There's a pretty good chance VVT phasers are limp when the oil pump is forced low given also low engine RPM. I am saying there's such a wild difference below 1,500.RPM when VVT are pumped up right, they must be limp under normal factory settings.

When repaired early camshafts may be worth saving if the dry cam lobes have not been shaved down.

Rickman30

My thoughts exactly Cali. I too think the VVT pin issue is the cause of the reluctor shifting, and like he stated, after starting, the engine breaths normally indicating cams are in time. I think that is also key in this diagnosis. A cam out of time would give power and MPG concerns on top of hard start, except in a no start situation, these would be unknown.

Mine has the check valve installed, but either it leaks, or my tensioner is weak. I'm leaning to the check valve because even it the tensioner was weak the pressure should sill be there. And, mine does not exhibit noise every cold start which would be a weak tensioner, the VVT rattle seems to occur once every six months or so.

In one year of ownership, have only heard twice, first was around Dec 22, second was around Aug. 23. but chain rattle about one in three cold starts, usually if the car is not driven for more than a week. If I drive everyday, trips longer than say 10 miles at a time, I am semi-rural based, then I hear the chains far less. I'm averaging about 3k miles per year. I mainly drive my Jeep WJ locally and the Benz out of town trips.

Another indicator, albeit the scope capture is by far the best to see which cam reluctor is off, is the MB procedure for checking chain stretch. Observing reluctor positions through camshaft position sensor holes, instead of all being off only the bank one intake would be off.

Also, this video is better than the one I was referring to, nothing is better than data backed diagnosis, especially with scope captures to verify faults. Thanks for sharing that. I recommend all to watch even if you are not planning on wrenching yourself, it helps with understanding the concern.

cluck

Thanks for tip Rickman30. Just watched the vid you were talking about and I'm hoping this is the fault. Will get back to you and let you know if it's the problem or not. Thanks again.

Rickman30

Thanks to CaliBenzDriver for the video, and additional information too. Please give credit where it’s due.

CaliBenzDriver

You know @Rickman30 I can only hope many of us share the same knowledge - We all contributes a little something... common knowledge, advanced knowledge, evidences are all useful to paint one true reality.

As long as we don't throw unrelated parts to known issues, the repair process is straight forward.

The way drama is purposely engineered into every system makes troubleshooting a challenging Easter-Egg hunt.

Dr. Deming is an American statistician who taught the Japanese industry about Quality control after WWII. There is very little randomness left into timely failures. 👏

The lifetime ATF, the extended oil change intervals, the "oil-in-harness /ECU", the cooked plastic sensors... all amount to expensive-savings!

Rickman30

Camouflaged Easter eggs at that.

Yeah I heard all that "Lifetime" chatter and said, That's gonna keep us techs busy.