Symptoms:
- can't change gears (will be stuck in 1st or 2nd based on W/S or C/S mode)
- instrument cluster W/S or C/S letter disappears (shows blank)
- instrument cluster PRND display doesn't highlight any letter
- unable to move shifter out of N or D (the gate to R is blocked) - need to restart car to unlock the gate
- car may throw a P0705 error code after a few minutes of driving
The culprit is a failed electronic component somewhere in the PCB. See video for more details (not my video). Some may find it feasible to repair the PCB, but personally I was unable to visually find the problem and didn't want to spend hours troubleshooting, so I decided to replace the entire assembly.
Tools required:
T20 screwdriver
T40 security screwdriver
10mm socket with extension
Snap ring (circlip) "open" tool - must open to at least 18mm or so
Slot screwdriver, pry tools for unlatching clips
T6 screwdriver if repairing electronics
Optional (if needed):
Files or sandpaper
Rust converter
Primer
Touch-up paint
The gear shifter originally installed in my car (MY2003, 5 speed automatic) was A203-267-54-24. According to this site, the latest compatible version is A203-267-91-24. I have no idea what the different variants are (there are 5-10 different versions of this gear shifter) so do your homework to ensure compatibility. Even the dealer didn't know which PN was supported.
This is the same procedure as the one for fixing the broken HVAC stepper motors. Remove and tilt the console assembly backwards and out of the way. Personally I also found it easier to disconnect the coaxial and 10P10C (RJ50) connector to get more slack.
The assembly is attached to the transmission hump by 3 10mm hex screws, 2 of which would already be removed along with the centre console. The 3rd screw is towards the front of the car.
The entire job is easier if the shifter is moved to the N position. Either turn the key to position 2 and shift into N, or push the override button (circled) to drop the internal gate.
Shifter gate override
Also note the "position" of the shifter with respect to the 3rd screw - the slots allow for some shifting (adjustment) during assembly at the factory. Ideally you want to install the new shifter in the exact same position, such that the linkage to the transmission doesn't need to be adjusted. There is technically a WIS procedure for that, but honestly it is best avoided.
Disconnect the 2 electrical connectors (facing the front of the car).
With those out of the way, disconnect the round cable connector. This cable tells the ignition module to allow the key to be turned fully to position 0, which allows for the key to be removed. Had no idea the system is mechanical instead of electrical. Push the connector tab (the one sticking out) inwards and rotate the connector. It comes out pretty easily. If your key is stuck, push the pin in the middle of the cable to deactivate the interlock.
Ignition lock cable
Lift the assembly 10cm or so and peek underneath. The shifter assembly is attached to the transmission linkage by a couple of bushings which are held in place by a circlip. Use the circlip tool to gently widen the circlip and slide it out of the grooves, in the direction of the bent "tab". The ends only have to be "widened" 1mm or so. Don't go too crazy here, or the clip will go flying. Some have suggested tying a piece of string or wire around the circlip to prevent it flying off, but personally I was unable to find a way to do this.
Take a good look at how the clip is attached. Notice how there are 3 points of contact with a "larger" circle, and 2 points of contact with a "smaller" circle.
Gear shifter circlip
Once the circlip is removed, the entire assembly can be lifted out of the car.
My "new" shifter did not include the 2 (1 rubber, 1 plastic) bushings. These pieces pop out easily and can be reused if undamaged during the circlip removal process.
I found that there was some rust along the edges of the hole where the shifter goes. Decided to fix this using some rust converter, primer, and touch-up paint. File off the rust and paint as needed.
Some of the online videos show people opening up the shifter assembly by unscrewing the (4) T20 screws. Guessing that was an older version - the one on my car was glued together. I had to grind away the tabs. Some people were able to pop the tabs apart with a kitchen knife and mallet. Do whatever works.
Shifter assembly glue tabs
The electronics module can be removed with some more disassembly. The module is attached to the assembly with (2) T20 screws. Open up the casing by unscrewing the (4) T6 screws.
I won't go into details here, other than that the electronics module is a "rotating" switch that is attached to the shifter shaft with 2 tabs. See photo. Be sure to understand how this works, or there is the risk of breaking off the tabs.
Shifter electronics tabs
The PCB tells the instrument cluster which gear it is in with the rotating switch which blocks a series of 4 optical sensors (not visible in photo, blocked by flat plastic piece) depending on the position. I am guessing that one of these sensors failed (either a failed component or a cold joint) but didn't notice anything based on a quick visual inspection.
Just realized the P0705 post has relevant documents for this job. Take a look. (credit C230 Sport Coup)
Lastly, the best way to deal with this problem in the modern era is to buy a used assembly from a wrecker or reputable online seller. I was able to source my (updated/latest compatible PN) unit for $140 USD before shipping. Meanwhile the dealer wanted $1502 CAD + tax for the same PN.
Ha, yeah I was going to say, I had a post here somewhere.
I also posted a list of the part numbers for 02 C230.
I originally bought one from an 03 at picknpull
but connectors were different and I couldn't see what gear I was in
on the dash. It gave out a few months later.
Then I had to wait for another to show up at P&P and
ended up driving to Richmond CA.(Yuk!)
a couple months later. Luckily I got it, and it worked...
until recenty it started sticking, not electical,
mechanical. But before I left Cali I had gone to P&P
for some other parts from an 02 sedan that was arriving that morning
and nabbed a spare, which I've now used.
Hopefully won't need this repair for a while on the new car and
now at least I know about the baking the board in the oven trick
and I have a spare working PCB from the one that failed for mechanical reasons.
My 2003 C230 is having gear shifter issues as well now, which seemed to start coincidentally right after I picked up my car from the dealer, which had changed transmission mount last year. Various symptoms include delayed engagement when shifting into drive (whether from Park into Drive, or from Reverse into Drive) where the dash will show it sitting in neutral for about 3 seconds before engaging into Drive.
Also, after car has warmed up after driving 15 to 20 minutes, while stepping on the gas and accelerating, the red light next to "D" on the gear shifter turns off. The light reappears when I left off the gas pedal. While accelerating, I can keep the red light next to "D" illuminated if I pull and hold the gear shifter backwards.
When I brought car back to dealer they rechecked their work and said they didnt cause the issue I was noticing, but they recommended replacing the gear shifter assembly. I declined at the time.
Now there is an intermittent new symptom where when coming to a stop I will hear a creaking/clicking sound with associated vibration from the gear shifter area itself, when coming to a quick stop. This newer issue comes and goes and made me worry more about impending failure that would leave me unable to shift gears.
So last week, I took it to a local indy shop and they also recommended replacing the shifter.
Will have them do the repair next week. when th3 indy shop test drove the car they could not reproduce the newest creaking/ vibration symptom from the shifter area.
Interestingly, for future reference, I came across this website that says they can rebuild your gear shifter if shipped to them:
Funny that artcle doesn't mention code P0705. Maybe that because it's the OBDII code not the MB one?.Hmm.
Your car not going into gear.,,,,was that just on the dash?
Or was actually not going into gear for 3 seconds? Because there is a rod that physically changes the gears.
But yes, if the shifter doesn't give the correct responses it puts you into limp mode 2nd gear only..
Shifting wierdness can be caused by these issues even just underfilled or overfilled trans.
I always perfer to underfill just tad as if overfilled even just a little the gear 'hangs' and doesn't want to shift.
And getting oil out is harder than putting it in. The fact that these things happen AFTER the car warms up,
I would
a. check the trans fluid level (when didd you have your trans serviced last?)
b. check the trans computer ie the TCU under the right floorboard. Easy to get to, just pull the carpet back
and pull the foot rest up, there mght be a couple plastic thumbscrews.
Disconnect the cable to the TCU and see if there's oil in it or the TCU.
c. Check the connector on the trans wherre it goes into the trans,
Is there oil in the wiring harness?
d. Pull a sample of trans fluid and hve it tested, make sure there's no glycol in it.
Your radiator couild be leaking coolant into the trans. This is very bad and needs to nipped in the bud as
quickly as possible. If it has an original Valeo branded one (you will know from date ccde)
...not good. You want to see Behr, or the B logo on it. That being said new Behr radiators are made in China.
So the one to get is Nissens.
Might be necessary to undo a few bolts in the piece that holds the hood cables to see which it is.
If that happens you will want to flush the trans and replace the radiator and hope it hasn't damaged the transmission. .
And always make sure the mechanic uses the correct Merceedes approved trans fluid AND
replaces the plastic piece (and the filter of course) that hold the connector to the trans erroneously known as a 'pilot bushing' to Merceedes as the Orings can leak especially when putting in new
fluid for some reason. Use OEM parts. Non- OEM gaskets leak. Ask how I know.
If everything I've mentioned here checks out you can breath a big sigh of relief. And if your issues ARE in the shifter, AND if the issues
are purely electronic and not mechanical, you can do something that sounds crazy,
Bake the shifter PCB control board in the oven. It's a provn fix that I didn't know about the 1st time I had it. Poke around and you will find the procedure for doing it.
Thanks so much for the detailed reply. You covered a lot of important issues for the M271 and it was a good reminder for me, a trip down old memory lane.
THe Valeo radiator coolant leak, my car had that issue years ago. The dealer did the repair under warranty back in ~2005, and at the time they only changed the radiator, torque convertor and did the transmission fluid flush. Later in 2010, car had shifting issues and dealer found glycol in the transmission fluid. THis time they changed the radiator to Behr, and changed the torque convertor and the Transmission. At that time, Mercedes ended up covering the cost of parts but I had to pay for the labor.
The car not going into gear: After putting the shifter into Drive, on the Dash i would see "N" and if I step on the gas, it really was in neutral. BUt after 3 seconds, I would feel the gear enagge and then "D" appears on the dash.
The TCU, Had brought the car to the indy shop this past Tuesday to do the shifter swap. I asked them to first check the TCU for any oil, and they called me back and said they did not see any oil. They also said the transmission oil level was OK and recommended I proceed with chanigng the shifter, so I told them to go ahead.
I got the car back the next day, and wow what a difference. So far everythign seems fixed. WIth the new shifter, when resting my hand on it, I now confirm that the old shifter had some issue where I could actually feel some play/movement in the shifter when going over bumps, sometimes when changing gear. This is gone with the new shifter in place.
Also with my old shifter, TIPtronic was out of action. it either wouldn't down shift or if it did, would be stuck on N on the Dash. TIptronic is now working again with the replacement shifter in place. I have to drive the car around more to see if any issues recur, but so far, so good.
Quote:
Originally Posted by C230 Sport Coup
Funny that artcle doesn't mention code P0705. Maybe that because it's the OBDII code not the MB one?.Hmm.
Your car not going into gear.,,,,was that just on the dash?
Or was actually not going into gear for 3 seconds? Because there is a rod that physically changes the gears.
But yes, if the shifter doesn't give the correct responses it puts you into limp mode 2nd gear only..
Shifting wierdness can be caused by these issues even just underfilled or overfilled trans.
I always perfer to underfill just tad as if overfilled even just a little the gear 'hangs' and doesn't want to shift.
And getting oil out is harder than putting it in. The fact that these things happen AFTER the car warms up,
I would
a. check the trans fluid level (when didd you have your trans serviced last?)
b. check the trans computer ie the TCU under the right floorboard. Easy to get to, just pull the carpet back
and pull the foot rest up, there mght be a couple plastic thumbscrews.
Disconnect the cable to the TCU and see if there's oil in it or the TCU.
c. Check the connector on the trans wherre it goes into the trans,
Is there oil in the wiring harness?
d. Pull a sample of trans fluid and hve it tested, make sure there's no glycol in it.
Your radiator couild be leaking coolant into the trans. This is very bad and needs to nipped in the bud as
quickly as possible. If it has an original Valeo branded one (you will know from date ccde)
...not good. You want to see Behr, or the B logo on it. That being said new Behr radiators are made in China.
So the one to get is Nissens.
Might be necessary to undo a few bolts in the piece that holds the hood cables to see which it is.
If that happens you will want to flush the trans and replace the radiator and hope it hasn't damaged the transmission. .
And always make sure the mechanic uses the correct Merceedes approved trans fluid AND
replaces the plastic piece (and the filter of course) that hold the connector to the trans erroneously known as a 'pilot bushing' to Merceedes as the Orings can leak especially when putting in new
fluid for some reason. Use OEM parts. Non- OEM gaskets leak. Ask how I know.
If everything I've mentioned here checks out you can breath a big sigh of relief. And if your issues ARE in the shifter, AND if the issues
are purely electronic and not mechanical, you can do something that sounds crazy,
Bake the shifter PCB control board in the oven. It's a provn fix that I didn't know about the 1st time I had it. Poke around and you will find the procedure for doing it.
