Come on, guys!!! More than 18 hours since I posted it, more than 40 people viewed it, and no solutions for my problem?
I know there are some very experienced technicians, diy people who can help me with some good advise.

Please help with my 2006 Mercedes C230 limp mode.
What is the problem, the transmission, the conductor plate, the ABS speed sensors, the conductor plate speed sensors, or ???
Thank you in advance.

 

It's the 0894 code in the transmission that's the issue. I suspect you may have a clutch that has fused.

 

Hi Rudeney,

Thank you for your reply to my problem. You may be correct, but obviously I'm trying to see any other possibilities less involved and less expensive.
My first thought when the problem started was that the transmission was defective, I was thinking about some damage to the brake clutches inside the 722.9 transmission ( I think they are K1, K2 and K3), only because the original symptom was like the parking brake was applied very firm, the car was very heavy to move.

But after doing the transmission fluid and filter change, I changed my mind since I didn't see metal filings o didn't smell burnt oil, no unusual or excessive gunk in pan or magnets, old fluid was about the right quantity / level. That along with the fact that 2 hard codes appear in the ESP/ABS module (they may have been there from the very beginning of the problem because I never thought to scan the ESP module when the problem started).
Those codes where C1130 L6/4 right rear speed sensor: Line monitoring and C1120 L6/3 left rear speed sensor: Line monitoring. These codes I was unable to delete with my Autel scanner.
NOTE: I can see all speeds from all 4 abs wheel speed sensors in my scanner, so I don't get the reason for displaying DTC codes. In one of many test drives, I noticed 1 mph difference in the Right Front wheel speed sensor. I understand that all should be the same speed or similar, but the incident didn't happened again.

My logic was that due to bad wheel speed sensors in the rear and/or a weak battery, the ESP/ABS got a power surge, applied the brakes by itself, and force the tranny to go into limp mode.
I replaced 2 rear sensors with used ones, no change.
I replaced the Yaw sensor in the trunk with a used one, no change.
I was about to buy a used ESP module to see if things improved, but I changed my mind because a mechanic with a top of the line Snap-On scanner was able to delete both rear speed sensors codes and they never came back.

But I still don't have ABS, ESP or Traction Control, they are disabled. And the car is in limp mode.

Of course I got multiple codes in different modules indicating low voltage, including in ESP module.
ALSO appeared code B1078 Fault in communication with component H3/1 (Alarm signal siren with additional battery) or there is a cable fault.
This code is CURRENT, it can be deleted but IT COMES BACK ALWAYS.
Normally, I wouldn't care about the alarm, but I do remember one night when I had to stop the alarm with the keyfob because it went off due to weak battery (?) again.

I would only pay attention to the alarm because it is a theft deterrent component, may be will affect the immobilizer??? Not sure about that. May be it has something to do with limp mode???
I removed the alarm, didn't see anything abnormal, then put it back in. Later I learnt that an internal battery in the alarm may be leaking on its internal PCB, creating code B1078. Sounds about right, I have seen pictures, I need to open the alarm and clean the board, but I'm not sure if it has anything to do with the transmission and limp mode.

Among many different codes that appeared and were deleted to never come back, I got:
P1789 Pressure control solenoid B short circuit
This could be inside the transmission??? This code has a "P" in front of the same 1789 already disclosed, but this code has a very different description.

The last unusual behavior is that when I disconnect and reconnect the battery, there are no messages in the dashboard about ABS, I am NOT required to turn left-right, left-right the steering wheel to reset the steering angle sensor. Well... I guess that confirms I don't have active ABS/ESP.

Hopefully someone has his/her own similar experiences or knowledge to share with me.
So far, it is confusing what the problem and solution is, but Rudeney, you may be right unfortunately for me. I may need new clutches, maybe 3rd gear???
Someone told me I may be able to get a transmission from the junkyard and put my own valve body with conductor plate an TCU VGS2. Any confirmation to that?

Thanks again Rudeney for your opinion, I appreciate it very much.

Please anybody who can give me alternatives???

Thank you all.

 

The thing is, you tried to push the car while in neutral and it was immovable. That's a physical problem - not an electronic issue. It could be a bad brake caliper that's locked-up, but the only other thing is in the transmission.