charleshartmann40
Seat Mii rough running and ECU error
Summary of the thread
A 2013 Seat Mii was experiencing rough running and reduced power, with an error code indicating a potential issue with the engine control unit (ECU). A possible cause suggested was a faulty main relay for the ECU, a common issue that can affect engine performance. The problem was ultimately resolved by a garage, which repaired the ECU and replaced the main relay, restoring the car's performance.
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4 comment(s)
charleshartmann40 (community.author)
Where is that relay located and how would I check it? Is it something I can do myself or does it need special car diagnostics equipment? I'm reasonably handy but don't want to make things worse!
idaheld7
The relay is usually in the fuse box, either under the bonnet or inside the car near the steering wheel. Check your car's manual for the exact location. Visually inspect it for any signs of damage, like burn marks. You can try swapping it with an identical relay from another circuit, like the horn, to see if the problem goes away, but be careful. If that doesn't work, it's probably best to take it to a workshop. They'll have the proper car diagnostics tools to confirm if it’s the ECU or something else causing the engine performance issues.
charleshartmann40 (community.author)
The problem is resolved. The garage did an ECU repair and replaced the main relay, costing 120€. The car runs like new now.
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SEAT
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MII
idaheld7
That sounds familiar. I had a similar issue with my Seat Mii, with reduced engine power and an error code. Have you checked the main relay for the ECU? It's a common culprit in vehicle electronics and can cause all sorts of ECU problems and mess with your engine performance.