rgfinn76

2012 C250 .... What is weird after I clear the code, it will not come back on unless I re-start the car within an hour of turning it off. Meaning I can drive to work, let it sit for hours, drive home and no code. However I can start with no code, Turn it off and start the car back up and get the code to trigger every time....Very weird, cars run fine regardless with code on or off

I read up about the conductor plate or a shift sensor below the shifter. Any ideas before I take it to dealer??

Mo420

Hi good Sir, I recently started to get the same error code (amongst others) on my 2011 C180, which the dealer advised me to replace my transmission control unit. Just wondering if you've had any luck in fixing your C250?

Mine drives fine, no issues at all. Tried to clear the code once, and came back again a few days later - I dont remember how long the duration was between shutting and starting the car though. Also just out of curiousity, what scanner are you using to clear/read codes?

rgfinn76

Good Morning, my fix was to replace the conductor plate on the valve body. Mine only had 57k and from what I read it can occur at this low mileage. Mine drove fine as well and only threw the code when the unit was hot.

I have a foxwell scanner NT530 with the Mercedes factory software loaded.

Best of luck getting yours repaired. 🤘

Mo420

Hi RGFINN good to hear back from you and thanks for sharing your experience! Please may I ask if you could share more on your fix? Did you have to go to the dealer to get it replaced, or did you ship out your conductor plate for repairs with a specialist? Mine has the VGS3 conductor plate, but my dealer still insist in replacing both conductor plate and the valve body, which ofcourse, they will bill me for an arm and a leg! I'm trying to get them to cover it on goodwill given my meticulous service history, but they don't sound too eager to assist

Just wondering, did you by any chance pull of the temperature reading when the fault occured? Mine happened around 92-96 degrees celcius based on the error log (please see attached). This seems like normal operating temperature, given the engine runs at around 90 degrees celcius.

Thanks for this too! I'm gonna be buying a scanner tool real soon too, once this COVID-19 thingy is over. Right now practically nothing could be shipped, and not many options available locally. I believe you had the issue for quite some time too and during that time, did your car drove fine or did it worsen over time? I'm thinking of driving my car for the time being first (and just keep clearing the codes when they come up with my scanner tool) whilst I save up enough holiday money to pay for the conductor plate!

Thank you good Sir and I'm really sorry for asking you so many questions!

Regards,
Mo420


Diagnosis

rgfinn76

Based on my failure code this was something that couldn’t not be repaired on the plate. They normally only repair the speed sensors etc. I also had the same TCU code as you. It looks like an identical issue to what I experienced.

We are kinda stuck to have to go the dealer route cause the conductor plate needs to be programmed and matched to you VIN, this sucks cause it’s fairly a simple repair.

I did have a 3rd party extended warranty in which the conductor plate was not covered. However my dealer was able to convince the warranty company that my valve body was a fault as well(not sure how they pulled this off) and ended up replacing the entire valve body which also contains the new conductor plate as a full assembly. Even with the extended warranty it still cost me about $1k. A full valve body will run around $2k to $2.5k

Conductor plate only will run around $1500 to $1800.

Again this sucks that these type of costly repairs occur at such a low mileage.

rgfinn76

No I didn’t happen to measure temperature when the error actually triggered. What was weird is if I made short trips down the block the error code would never trigger.

When I did go on long runs, the code would not actually show up until I actually restarted the car it after the long run.

Mo420

Thank you for the helpful insight Mr. RGFINN. I'm afraid it is as I feared, only the dealer can do the repair. And yes, it really sucks to have such expensive damage at such a low mileage and well taken care vehicle.

My plan now is probably just to use the car for the time being. Did you do the same, and did you notice your symptoms progressively worsen over time?

It also sucks that this expensive repair is just to get rid of the CEL, and not to actually "fix" something. Oh the joys of the 722.9 transmission

Regards,
Mo420

rgfinn76

There were no symptoms at all car fine fine, no shifting issues, no locking gears etc. only indication was the stupid CEL.

i read somewhere else on here where a guy was driving around with the same code for two years and just kept clearing the code. I’m not 100% sure of any long term damage.

I finally decided to repair mine cause I only had 30 days left on my extended warranty.

mercw140

forgive me for my confusion. I have a 2006 SL350 with p0705. The transmission will drop out of gear to neutral once or twice a day. I've been doing some research and I've seen a few videos of guys replacing the part. Can someone please verify this.

Mo420

Hi mate, please could you clarify which part exactly is being replaced?

mercw140

hi mate. its one of the 2 speed sensors. y3/8s1.
Thanks in advance

c250benz12

the boost sensors?