W211 2007 conductor plate speed sensor repair.

[boxer 01]

Hi I am having issues with my 7g transmission and fault codes are pointing to the speed sensors being at fault on the conductor plate in transmission. There are companies that repair these plates for a couple of hundred pounds, but I was wondering if anyone has replaced these sensors, and if it's straight forward to do. I have done some research and sensors aren't that expensive but installing looks to be a bit tricky as it's plastic.
I would like to hear from any members that have replaced these sensors or have any advice.

 

[Dodipops]

Never replaced them myself but have had the companies do so on more than one occasion and have always worked well.

 

[Petrol Pete]

Mercedes – 722.9 7G-Tronic Valve Body & Conductor Plate – Must Read – MB Medic

www.mercedesmedic.com

 

[wongl]

If you feel comfortable changing the transmission ATF fluid and filter (requires dropping the gearbox sump), then it is one more level deeper from there (something like 18 to 19 more screws to remove and drop the valve tray). I have never done this myself but have watched Steve done it a couple of times to my two A-Classes and an E-Class. I used ECU Testing to repair the speed sensors on my two A-Classes, but for the E-Class Steve happened to have a spare one laying around.

Edit: The speed sensor on the A-Class looks like complex assembly with several components attached to it, but the speed sensor on my E-Class looked like a passive thin "metallic looking circuit board" without any components attached to it. Edit2: I think on the E-Class it was just the conductor plate and not the actual speed sensors unlike the A-Class.

 

[boxer 01]

If you feel comfortable changing the transmission ATF fluid and filter (requires dropping the gearbox sump), then it is one more level deeper from there (something like 18 to 19 more screws to remove and drop the valve tray). I have never done this myself but have watched Steve done it a couple of times to my two A-Classes and an E-Class. I used ECU Testing to repair the speed sensors on my two A-Classes, but for the E-Class Steve happened to have a spare one laying around.

Edit: The speed sensor on the A-Class looks like complex assembly with several components attached to it, but the speed sensor on my E-Class looked like a passive thin "metallic looking circuit board" without any components attached to it. Edit2: I think on the E-Class it was just the conductor plate and not the actual speed sensors unlike the A-Class.

Ive got all the stuff ready for dropping the conductor plate out and replacing again but it's sods law, car has been running good for the last couple of weeks even when I give it some Welly. I have seen a few videos of people changing the speed sensors and it's a bit hit and miss and nobody actually shows the conductor plate refitted and actually working also the actual quality of sensors I would be purchasing is unknown, all Chinese but varying tremendously price wise even though they all look very similar.
So I think ECU testing or Essex recons is where I will send, when I get around to it. I'm getting to a stage in life where rolling around on the floor under the car takes its toll and the recovery period for my bones is getting longer so I'm in no rush at present.

 

[BlackC55]

I always tend to but new. The reason for that is that they work first time and its a reliable repair.

 

[boxer 01]

I always tend to but new. The reason for that is that they work first time and its a reliable repair.

I would go for new too but due to the age and market value of the car the cost of new plate and coding is not feasible, so I have to go for the next best option, which is refurb and DIY.

 

[wongl]

I'm getting to a stage in life where rolling around on the floor under the car takes its toll and the recovery period for my bones is getting longer so I'm in no rush at present.

Same here!

 

[boxer 01]

Just to finish off the thread, I removed the conductor plate last Monday and sent it off to ECU testing for repair, It was returned after repairs and fitted back in on Saturday. All seems good although not had chance to go for a proper run. All credit to ECU testing for their efficient service.
Dropping out conductor plate wasn't too bad although it's a messy job (oil dripping everywhere), refitting was a bit stressful as the aluminum bolts securing valve body to transmission are very fragile and seemed as though they were going to snap even though the torque settings were 4nm and then 90deg. My opinion is if you can do a transmission service you shouldn't have a problem removing and refitting conductor plate, just make sure you keep everything super clean, and use lint free clothes.