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2006 C220 CdI The automobile is now immobilised in a certain gear and is unable to start.


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Could someone provide a clear explanation of the current situation, please?

While driving, I reached an intersection. When I tried to accelerate, the automobile remained stuck in a very low gear. The indication was D, however it resembled more closely the first position.

Upon reaching a tranquil section of the road, I brought the vehicle to a halt. However, the gearbox became immobilised, rendering me unable to restart it.

I contacted the recovery service, but they informed me that it would take around three hours for them to arrive. Unexpectedly, I was able to start the process and for a duration of 30 seconds, the gears were unobstructed, but then became immobilised in first gear once again. I only operated the vehicle in first gear for a distance of just two miles till I reached my residence.
I get that there is a switch located underneath the lever, since my acquaintance had a similar problem with his E Class few months ago.
If someone could validate my thought process and direct me to locating this switch, I would really appreciate it.

Am I allowed to buy and install this component as my friend's part was sent for repairs and cost about £200?

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Is the gear change lever assembly? Is the vehicle equipped with coding and programming capabilities?
Therefore, if I purchase a secondhand item, it will not function unless it has been programmed with the necessary code.

Thank you.

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Based on my experience with the CLK, and considering the lack of input from others, I will provide information assuming that the C class and CLK are very comparable.

There is a possibility that there is a lever for releasing the emergency gear selector. Raise the central armrest in order to access the storage compartment. Detach the plastic pan located just below the gear selector. Insert your hand inside the opening and locate the narrow aperture at the front. Place a ballpoint pen or a similar object into the designated slot and push down on the lever. This disengages the gear selector interlock. The gear lever should now be unrestricted in its movement. This process need to be included inside the user handbook.

The electronic gear selection mechanism in the parts catalogue (EPC) is said to have a 'anti-theft coded' feature. It is not. Any item that has the same component number will function properly.

Prior to purchasing a new item, I would recommend having the fault codes examined to see whether the issue is with the ESL or not.

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Indeed, I have located the little button responsible for disengaging the lever. However, after successfully doing this task, the Starter remains unresponsive due to its erroneous perception of being engaged in a gear. Additionally, the gear indicator light fails to provide any information.
During the test, I received an error code indicating a problem with the Gearbox Range Sensor. The specific code is P0705. It seems to be prevalent on this particular iteration of Mercedes. Following a conflict, I have successfully detached the lever box together with its sensor and have subsequently located a business to do its repair. Although it will be expensive, I must give it a try.
Thank you.

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Rudy7831, your automobile is equipped with a variant of the 722.6 gearbox, which is widely used in several vehicles, including cars, trucks, and buses. There is a plethora of useful knowledge available online.

What is the mileage of this automobile and when was the gearbox last maintained?

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I replaced the gearbox oil and installed a new strainer around 25,000 miles ago when my vehicle had reached 150,000 miles.
I believe I have correctly identified the issue with my Mates E Class vehicle, as it had a similar malfunction and error number a few months ago. It was determined that the sensor located within the shift lever box was the cause of the problem.
An unusual occurrence is the infiltration of gearbox grease into the ECU when one does internet research.
The component responsible for gear shifting is now being sent to a business specialised in testing electronic control units (ECUs).

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I am acquainted with the module since I experienced a similar situation. In my situation, the issue was a misalignment of the optical module responsible for detecting the movement of the gear shift lever in both forward and backward directions. I had both of the symptoms that you mentioned.
Does your code reader have the capability to determine the position of the gear lever? I am now unable to recall the specific system under which it is mentioned. However, I will verify this information later today. If such is the case, you may attempt to realign the optical module on your own if you possess skill with tools and a soldering iron, and have a few hours of free time available.
I suspect that there was a dry solder junction in this module. I disassembled it, meticulously re-soldered all accessible connections, and then reinstalled and realigned it. The mounting screws are placed in slots that allow for little adjustment between the actual position of the gear lever and the position detected by the optical sensors. To accurately re-position the module, you may make minor modifications and compare the actual position of the lever with the value obtained from the OBD reader.
Fortunately, I have not had any other issues with it since then.
If I remember correctly, before the issue was resolved, just clearing the fault using the OBD reader will temporarily restore normal performance, usually for a distance of only a few miles. The first failure of the gear shift mechanism was attributed to the left/right '+'/'-' action.

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Thank you for responding.
It is peculiar that when I was not touching anything and exiting a crossroads, the situation did not alter. Halting was an unfavourable decision, since it would not resume due to the mistaken belief that it was still engaged in a gear. Attempting the task again after removing the key proved beneficial.
I own the iCar soft reader, but, it failed to detect any faults. Consequently, I resorted to using my previous Sealey reader, which successfully identified the defect.
Currently, I am unable to take any action on it as the postman will be collecting the item imminently.
There is a local Mercedes expert that attempted to fix my friend's car with the same issue but was unable to find a solution, therefore I will take on the task myself.
There is a firm that specialises in repairing electronic control units (ECUs) and they are known for their efficient 2-day turnaround time. The defect you mentioned is one of the most often encountered issues they deal with.
I will provide an update if it is successful. The task has been completed well, with a total of 194,000 units, therefore there is no reason for complaint.

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Verifying the presence of ATF Accessing the TCU (Transmission Control Unit) in a car is a simple task that does not need lifting the vehicle. The TCU is conveniently located in the passenger footwell, making it easily accessible. The process of accessing and working on the TCU typically takes about 30 minutes and does not require any specialised equipment. Automatic Transmission Fluid (ATF) enters the Transmission Control Unit (TCU) when the o-ring on the TCU plug breaks on the gearbox. The replacement component is inexpensive and readily available on the internet. It is worth noting that some people anticipate detecting the scent or presence of Automatic Transmission Fluid (ATF) on the wires during examination. However, I believe that the fluid has the ability to seep into the individual conductors inside the wire insulation.

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The gear lever unit is now undergoing testing and repair by the ECU specialists. I am awaiting their findings.

Out of curiosity, I saw that the gear lever box is equipped with enlarged holes, presumably for the purpose of adjustability.
What would be the appropriate procedure for setting it up?
Thank you.

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While you are awaiting the return of your lever, I suggest taking a moment to examine the TCU, as mentioned in my previous article. Although you currently do not exhibit any indications of oil wick, it would be advisable to thoroughly inspect the Transmission Control Unit (TCU) for the presence of Automatic Transmission Fluid (ATF).

No risks or potential negative consequences.

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To remove the carpet, first detach the soundproofing block by pulling it down. Then, use a 10 mm socket to unscrew the four plastic nuts. Next, lower the metal plate that is securing the TCU (Transmission Control Unit). Finally, loosen the single 8mm bolt that is keeping the TCU in place. Following these steps will successfully complete the removal process.

Straightforward.

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It didn't cross my mind while I was replacing mine.
Based on my understanding, I presume that your setup is similar to mine, where there is a mechanical linkage between the shift lever and the large gearbox working lever underneath the vehicle. These two components are linked by a clevis pin, which may be somewhat challenging to re-connect. In this scenario, the link indicates that the shift mechanism effortlessly aligns itself in the correct position during reassembly.
If the position of the shift lever corresponds to the displayed gear on the dashboard and the gearbox has successfully engaged the corresponding gear, then there is no need to be concerned.

By the way, during reassembly, ensure that the clevis pin connecting the two levers is firmly positioned, with the locking tab securely engaged in the groove of the pin. I did not intentionally remove the tab, and as a result, I conducted the test drive with the pin in a loose state, on the verge of detaching from the automobile. Fortunately, I discovered the pothole on the way. Valuable knowledge acquired.

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I have not yet verified this, but I am curious to know whether oil would have an impact on an Engine Control Unit (ECU). Or how would it be?
I have seen some electrical devices that are immersed in oil as a means of maintaining optimal temperature.
I am not expressing disagreement, but rather expressing curiosity about how it impacts various aspects. Brake cleaner would likely be effective in removing the dirt or grime.

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The presence of oil in the TCU disrupts its performance and leads to 'short circuits'. The whole conductor plate and its electrical solenoids within the gearbox are immersed in Automatic Transmission Fluid operating at temperatures between 80 and 90 degrees Celsius.

The distinction is in their intentional design to function in such a manner. The TCU was placed in the passenger compartment, indicating that it was not otherwise. Although it is improbable that this is the issue you are facing, I have shown in post #9 how simple it is to verify. The decision is yours.

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I successfully inspected the ECU. Is this the one I assume? According to Google's statement.
All terminals and connections are devoid of moisture.
There are peculiar blemishes on the rear insulation that first seemed to be oil but likely have been there from the beginning.
Currently, I am patiently awaiting the repair of my gear shift mechanism.

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The issue has been resolved.
I highly suggest ECU Testing as a reputable organisation. High-quality work and informative content. The fix is costly.
If it weren't for the abysmal quality of service provided by Royal Mail, the task would have been completed five days ago.
Considering my intelligence, I decided to reposition the clip on the changing rod pivot from the bottom. It is not advisable for me to lie on my back in my driveway.
The journey to refurbish was successful.
Thank you everyone for the assistance and information.

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