Why is it always recommended to replace the mechatronic unit rather than repairing it? This can be better illustrated with an example:
Let’s say your car’s gearbox is having trouble shifting from 3rd to 4th gear, and you’ve retrieved a fault code (Pxxxx) indicating a problem with shift lever 3. What could be causing this fault code? There are three possibilities: the mechatronic unit, the shifting lever (a mechanical part of the gearbox), or the clutch, which may not be disengaging properly and causing resistance for the shift fork.
Replacing the mechatronic unit is a relatively straightforward process that doesn’t require removing the entire gearbox. On the other hand, overhauling the gearbox is a much more expensive and complex task, and replacing the clutch necessitates the complete removal of the gearbox.
Out of thousands of diagnoses, we can provide a rough estimate of the potential causes for this specific issue. Approximately 50% of such problems are attributed to the mechatronic unit, 35% to gearbox mechanical issues, and 15% to a sticky clutch causing shifting problems.
Therefore, the logical conclusion is to start by repairing or replacing the mechatronic unit. It’s a cost-effective and relatively simple solution. Imagine you send the mechatronic unit to a repair shop, where they replace some solenoids. However, a significant portion of the mechatronic unit cannot be replaced with new parts. After a week, you reinstall the mechatronic unit, drive the car, and encounter the same shifting problem from 3rd to 4th gear. Is the mechatronic unit still the cause of the issue? The answer is uncertain. That’s why it’s strongly advised not to attempt repairing the mechatronic unit yourself because you’ll never be certain of the problem’s source. You might contact the repair shop, but it’s impossible to inspect a mechatronic unit thoroughly. The only way to assess it is by physically installing it in a car, conducting a test drive of at least 200 kilometers, and carefully analyzing digital adaptation values and checking for shifting and drivability issues. Unfortunately, this post-repair assessment is often not carried out.
The optimal solution is to use an overhauled exchange unit. Why? Because the original mechatronic unit you have is from another car that had a different issue, such as difficulty shifting into reverse gear. This unit was repaired and sent to you. If you install this unit in your car and the gearbox problem persists, not shifting from 3rd to 4th gear, you can be certain that the mechatronic unit is not the root cause; it’s likely a mechanical problem within the gearbox.
This is why we at TVS recommend always going for a new mechatronic unit or, as a Plan B, using an overhauled exchange unit. We strongly discourage attempting to repair your original mechatronic unit. TVS keeps mechatronics units in stock, pre-programmed and ready for immediate shipment. After you’ve installed and received the new mechatronic unit from us, you can send back the old unit. This exchange process is much quicker than attempting to repair your original mechatronic unit.