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Mechatronics FAQs: 10 Mechatronics Unit Questions Answered

Welcome to our Mechatronic unit lesson! Today we’re going to be answering some of the most important questions we are asked about these clever bits of kit, starting with…

What is mechatronics in a car?

In automatic vehicles, the gearbox is controlled by the mechatronics unit. This is an electrohydraulic robot which is basically the brain of the gearbox. It tells the gearbox when to shift up and down. Although incredibly clever, these units fail just about as often as your clutch, so they are a standard repair item. That being said, it’s important to ensure that the fault is with the mechatronics and not something else as these are pretty expensive to replace. There’s then also the issue that 1. They are very tricky and technical to replace and 2. You need to have the right specialist skills, diagnostic equipment and tools to do the job.

How does a mechatronics unit work?

The mechatronic unit works by receiving electronic signals and converting them into hydraulic power to control the gearbox.

What cars use mechatronics?

Any car with a DSG gearbox will be using a mechatronic unit to control it. DSG stands for Direct Shift Gearbox and was developed by the Volkswagen group. These cars include Volkswagen, SEAT, Audi, Kia, Hyundai and Ford. If you are unsure, speak to our team and we can tell you more about your gearbox.

Can a mechatronic be repaired?

Sometimes, yes but also no. It depends on how badly broken the unit is and this will only be known once a thorough diagnostic report has been completed. At CCM, we don’t repair mechatronic units in-house as we use a reputable third-party supplier for this but we do process all the diagnostics, removal, replacement and adaptations of the mech unit.

Callum at technician at CCM Gatwick works on a mechatronic unit
Callum a technician at CCM Gatwick works on a mechatronic unit

How do you know if a mechatronic is having issues?

There are some pretty obvious tell-tale signs that your mechatronic unit is faulty, these include:

  • Bad gear selection
  • Getting stuck in gear
  • No gear selection
  • The gearbox will only select odd or even gears
  • Dashboard warning light of PRNDS, orange spanner, gear wheel or cog
  • Going into limp mode
  • A bump or surge of power when shifting
  • Jolty gear changes
  • Unusual noises during gear changes or braking
  • Scraping or grinding noises when stationary or pulling away

If you’re experiencing any of these noises, it’s time to book your vehicle for an investigation.

How long does it take to replace a mechatronic?

So, this isn’t something that we can say as a dead certain for all mechatronic repair jobs, but we can provide a rough estimate on the timeline you can expect.

  1. 1 hour diagnostic to review the issue and put together a repair plan
  2. 2 hours to remove the mechatronic
  3. The ordering of the new mechatronic can take 7 – 10 days to arrive with our team
  4. 4 fours to fit and reprogram the mechatronic
  5. 1 hour for run adaptions and take on a thorough road test

There is some other work that may well need doing as well including a gearbox oil and filter change or gearbox flush if the oil is contaminated. In the worst-case scenario, the mechatronic doesn’t readapt because the clutch is worn too low so we need to replace the clutch kit and flywheel. This can add another £2,000 – £2,500 onto the job.

This is why regular servicing of your gearbox is so important if you want to avoid a hefty repair bill.

A mechatronics repair kit on a workbench at CCM Gatwick
A mechatronics repair kit on a workbench at CCM Gatwick

How does a mechatronic unit fail?

Like most things, there are a few reasons why your mechatronics can fail.

  • Cracking around the accumulator
  • Hydraulic pump motor failure
  • Broken speed sensor
  • Burnt out circuit board
  • Pressure sensors
  • Clutch position sensors 1 and 2
  • Plus a multitude of more issue

How often should a DSG gearbox be serviced?

It is recommended that DSG gearboxes should be serviced at around every 40,000 miles or 4 years. What you need to be aware of as a DSG owner is the difference between a gearbox oil change and a flushing service. The oil change sees the technician draining the oil and replacing the filter which only removes around 60% of the contaminated oil. You then run the risk of your lovely new oil quickly becoming contaminated. With an automatic gearbox flushing service we can remove the oil from your car whilst running the gearbox in gear, then add a flushing fluid treatment to break down contamination. After this, we fit new gearbox filters and then add fresh, clean oil.

While we are always happy to offer an automatic gearbox service, it’s worth noting that, if you are experiencing issues with your gearbox then it’s best to have an initial diagnostic check first.

Can launch control damage the gearbox?

Unfortunately, yes. Launch control works by keeping the engine at a high RPM and then quickly releasing the clutch when you release the brake pedal. Repeated use of this does put the gearbox and clutch pack under stress. This is because the clutch pack is a set of friction plates and using the launch control wears them out faster. It’s also worth noting you should always let your gearbox warm up before hitting the launch control.

What to do if you have problems with your mechatronics?

The best thing you can do for yourself, and your car is to bring it to our team. We have multiple technicians with DSG Level 3 qualifications and years of experience with mechatronics removal, repair, and replacement. Trust us when we say this isn’t a job for any run-of-the-mill garage, and definitely not one for you to be doing on your driveway. As we mentioned earlier, these are incredibly technical pieces of kit which you need the correct diagnostic equipment and tools to do the job.

Trust our DSG Experts

See how we can help your gearbox

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