VW Suran ECU Power Loss, Expert DIY Diagnosis Guide

A similar issue occurred with my VW Polo TSI from 2018. The symptoms matched exactly, reduced power and stored error codes in the engine control system. The main relay failure was causing intermittent power supply to the ECU. This created multiple problems: Unusual engine power reduction, System would not retain error codes properly, Engine control became unreliable, Warning lights appearing intermittently The vehicle electronics diagnostic revealed a defective main relay circuit affecting the entire control system. This required: 1. Full system scan 2. Main relay replacement 3. ECU repair and recalibration 4. Complete system reset This is considered a serious electrical issue since it affects core engine management. The main relay serves as a critical component connecting the ECU to various engine control modules. Without proper repair, it can lead to complete engine failure or permanent ECU damage. Best approach is having a specialized workshop perform proper diagnostics first. They should check the main relay circuit before replacing any expensive components. The repair itself is not highly complex for experienced technicians with the right diagnostic equipment.

Thanks for sharing those details about your Polo TSI repair. Did similar ECU repair and system reset issues pop up afterwards? I had a comparable situation with my Spacefox last month, complete engine performance drop and multiple error codes. After the automotive electronics specialist diagnosed it, they found a faulty computer module that needed replacement. Would be helpful to know the total cost you paid for the diagnostics and repair work. My bill came to around 850€ for everything, but prices seem to vary quite a bit for this type of work.

Good news, since getting the main relay fixed on my Polo TSI, the automotive electronics have worked flawlessly. The system reset and ECU repair completely resolved those power and error code issues. No recurring problems in the control system at all. The total cost was actually quite reasonable at 120€, which covered both the parts and labor. This was much lower than your computer module replacement since only the main relay needed replacing. The vehicle electronics diagnostic confirmed this was the only faulty component causing the ECU issues. A qualified technician completed the repair in about an hour. The process included running a full system scan, replacing the relay, and performing a final control system check to ensure everything was functioning correctly. For reference, main relay failures are generally less expensive to fix compared to complete ECU replacements or more complex automotive electronics issues. Getting an accurate diagnosis first definitely helped avoid unnecessary costly repairs.

After seeing all those suggestions, I decided to take my Suran to an automotive electronics specialist today. The car diagnostics showed the problem was actually simpler than expected, just a corroded connector affecting the ECU communication. The technician cleaned the connections, performed a full system scan, and recalibrated the engine control modules. Total cost came to 180€ including the diagnostic fee. Much better than the 850€ estimate another shop gave me without even checking the vehicle electronics properly. The engine performance is back to normal now and all error codes are cleared. Really glad I asked here first and got that ECU repair advice instead of rushing into expensive replacements. The whole repair took less than 2 hours.