SteveL1

Have error code P0718 Input/ Turbine SpeedSensor A circuit intermittent. Won't shift out of limp mode & check engine light is on. Had car towed to dealer.

What should I expect to hear and any guess at an approx cost? I've read that it could be a speed sensor, a valve body or worse. I've also read that this is a fairly common problem but Mercedes refuses to acknowledge any fault. Car has 112,000 miles on it and otherwise in very good shape.

Any chance that the dealer will cover anything?

Thanks for any help you can share!

Glyn M Ruck

P0718 = Input/Turbine Speed Sensor Circuit Intermittent.

Usually a sign of Siemens conductor plate issue.

SteveL1

Thanks Glyn, I hope you are right and it only needs the conductor plate. Do you think I'm better off telling the service tech that I have done my research and know of the common problem before they have a chance to come back with something worse or wait and potentially have to dispute their diagnosis? My regular service tech is on vacation this week so I have a newbie filling in for him. My regular guy knows that I do all my own routine maint and frequent this board for info.

Thanks again for all your help!

johnand

Yep, likely conductor plate. As long as you have the newer valve body, then the conductor plate replacement is the fix. Usually runs $1000-1400.

Glyn M Ruck

I would tell them you've done your homework & then see what they come up with. Trouble is that it depends which transmission is fitted to your car. Very early ones required the whole valve body replaced. On your side is that most of them went into the S Class ~ see other active thread in this regard.

Glyn M Ruck

Oops! John & I posted over one another.

SteveL1

Hopefully it's the later version as the car was built in late April of '07 and if I remember correctly, the started production of the '07s in June. Keeping my fingers crossed! This has been an expensive year for the car! New manifold, cooling fan, cam sensors and it needs brakes.

SteveL1

Dealer says its the conductor plate and will cost $1,200 for everything. Guess it could have been worse but this car has cost me a fortune this year!

Now the question is, what should I expect to go next? Currently have 113,000 miles and have replaced the manifold, cooling fan, cam sensors and magnets, conductor plate and front struts. Seems like I've had all the common issues unless I've missed something.

Glyn M Ruck

It's a crap shoot but you should be clear for a while. Watch your front castor bushes for cracks & silicone fluid leaks. Common problem but fortunately a cheap fix.