Random Cutting Out Seat Leon 2014 1.2

[LukeS]

Hi everyone,

I’m having an issue with my 2014 Seat Leon SE Technology TSi Semi-Auto (1.2 Estate, 60,000 miles) and was hoping for some advice.

The Issue:​

A couple of weeks ago, on my way to work, the engine cut out. The accelerator became unresponsive, and there were no revs. The only warning on the dash was a "Brake!" message. After pulling over and restarting, the car drove fine for the rest of the journey (about 30 miles), and again on the way home that evening.

However, the next morning the same thing happened. I restarted the car, but this time the issue returned about 5 miles later, along with an orange engine management light.

Diagnostics:​

I took it to a garage where they couldn’t replicate the issue. Diagnostics showed the following code:

• P084100: Transmission fluid pressure sensor/switch A range/performance.

They told me to monitor the situation. Unsurprisingly, the issue happened again, so I went to a second garage. They found the same code as well as:

• U010300: Lost communication with gear shift module
• B10ABF0: Refrigerant pressure below lower limit

I was referred to a gearbox specialist, who explained that the transmission fluid pressure sensor is part of the mechatronics unit and recommended replacing the entire unit, quoting around £2000. However, they weren't confident that this is related to the engine cutting out. They suggested another garage with "dealer-level" diagnostics for VAG software updates.

Next Steps:​

Another transmission specialist also believes the mechatronics unit might be causing the issue and gave me a similar quote.

Questions:​

1. Has anyone experienced similar issues with their Seat Leon?
2. Is it worth replacing the mechatronics unit, or should I seek further diagnostics for software updates or other potential causes?
3. Any other suggestions for dealing with this problem?

Note: The issue seems to happen randomly, both at speed (55-60mph) and in slower traffic or while stopping at junctions.

Any advice would be greatly appreciated as I’m not very mechanically inclined, and I want to avoid unnecessary costs if possible.

Thanks in advance!