How to Solve a Jerky Transmission in a Mercedes A-Class
Mercedes – Benz and reliability are synonymous with each other. The two are inseparable, and such has been the case since the brand first entered the automotive world in the early 20th century. Even when Mercedes started commercial production, the huge numbers didn’t affect the brand’s reliability as much as other makes and models.
The occasional vehicle developed a fault, but the issue never consistently existed in any Mercedes car. Due to that, German cars started to become famous across the globe for their reliability and durability.
Perhaps, that is why Mr H put his trust in the Mercedes brand and bought the A-Class. He was confident that the vehicle would last him decades and would not give him too much trouble. Unfortunately, Mr H’s Mercedes developed a gearbox fault a few days after purchase.
Our customer couldn’t believe his four-year-old Mercedes had developed such a major issue but he was confident that RM Motors would be able to find the solution. He put his trust in our technicians and hoped for a speedy repair.
Luckily for our client, we have lots of experience handling transmission issues like this. So, when we first heard about the issue, we did not hesitate even for a second and immediately started with the verification and diagnosis processes.
The Diagnostic Process
Our Mercedes technician listened attentively to the client’s complaints, all the while making notes of the symptoms. We would use this initial knowledge later to guide ourselves throughout the repair. So, the client needed to explain everything in as much detail as possible.
After the client had elucidated the entire issue, our Mercedes specialist initiated the RM Motors multi-step diagnostic procedure to help make sense of the issue. The diagnostic process we use at RM Motors helps our technicians to cover all their bases and find out the actual fault hidden underneath the layers.
The client had talked about jerky and prolonged gear changes in his A-Class, which sounded odd to our Mercedes expert. Something like this shouldn’t happen, but we were seeing it with our own eyes.
Regardless, our Mercedes technician started the vehicle and went on a test drive. We had to verify the client’s complaints and also ensure there was no other issue contributing to the transmission problem.
It was evident during the test run that the transmission was faulty, and the gear changes were indeed jerky, as the client had described.
What was causing this issue? We had to dig in deeper to find out.
At this moment, we were thinking about multiple reasons affecting the A-Class, but our Mercedes specialist wasn’t going to leave anything to speculation. We had to be completely sure before employing any kind of solution on the vehicle.
Therefore, our Mercedes technician decided to conduct a complete fault scan of the vehicle to look for hints. The following error codes turned up on the search:
- 056200 – It refers to a power supply circuit 87 Undervoltage failure. The code is registered in the Engine Control Unit (ECU) but it should also be noted that most transmissions are controlled through the ECU and not through a TCU (Transmission Control Unit)
- 051300 – This code activates when there is a battery voltage problem or when the transmission is not working properly.
The vehicle scan confirmed that the fault indeed lay in the transmission area, but it did not specify the exact source of the issue. To find that out, our Mercedes expert had to look further and trace back the whole transmission system while inspecting its components.
Our Mercedes specialist looked at the software version of the transmission to ensure the car had the latest update. Thankfully, all was good in this department, and the software version was up to date on Mr H’s Mercedes.
Moving on, our Mercedes specialist tried to inspect the wiring and found that to be in perfect shape as well. The gearbox was receiving the right input from all the sources, including the Transmission Control Module (TCM). So, our technician load-tested the power and ground wires to check their integrity, and they worked fine as well.
All of this meant that there was something hidden underneath the covers, waiting to be discovered.
Our Mercedes technician wasn’t going to let any opportunity slide past him, so he did a bit more research into the issue. Finally, he found the mechatronics component to be at fault. The said part is responsible for shifting the gears, and it was damaged.
Finally, after so much research and hard work, our Mercedes expert discovered the hidden fault, and the only thing left now was to employ the solution and hand the car back to Mr H.
The Solution
Our Mercedes specialist used his knowledge and the multi-step diagnostic procedure to help diagnose the fault in the 2018 Mercedes A-Class vehicle.
The only way forward now was to repair the old part or install a brand-new component in its place.
We presented that choice to our client, and with our advice, he chose to go with the brand-new component.
So, without wasting a second, our Mercedes specialist started to disassemble the transmission and replace the mechatronics unit. It took him a while, but our Mercedes expert managed to do the entire process in a short amount of time.
Once that was done, we had to start the teach-in process to register the new mechatronics unit to the A-Class vehicle. If we skip this process, then the Mercedes A Class would not recognise the new part and the issue would persist.
We used the official Mercedes Benz Xentry Kit 4 to encode and program the fresh unit to the ECU. Once that was done, we wrapped up the repair by clearing all the fault codes in Mr H’s Mercedes and proceeded to call him to pick up his vehicle.
Summary
Mr H visited RM Motors with his Mercedes A-Class, complaining about a jerky transmission and hoping that we would solve the issue. From the get-go, we could see that the problem was mechanical, but to be sure, our Mercedes specialist used our multi-step diagnostic procedure.
As a result, we found out that the mechatronics unit inside the transmission was faulty. It had malfunctioned and the only option for Mr H was to get it repaired or replaced with a fresh new unit.
Luckily, the client chose to go with the replacement, and we happily obliged. Once the fix was complete, Mr H picked up his vehicle from our garage and thanked our Mercedes technicians for doing an impeccable job.
We wouldn’t be surprised if Mr H chooses RM Motors to be his first choice for future repairs.
If you have an issue with your Mercedes or your Mercedes needs a service then make RM Motors your go-to Mercedes garage. Call us on 01924 456666. You can expect dealer-level know-how and better-than-dealership value at RM Motors.
