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marioschneider68

Audi SQ5 ECU Failure After Suspicious Service Work

Fault stored

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Loss of engine power

Looking for advice, my 2015 SQ5 with 73k km is acting up with reduced power and stored error codes. The engine control unit might be the culprit. Had some questionable work done at my last mechanic visit and now wondering if anyone has dealt with similar ECU issues. Any recommendations on automotive electronics specialists who know their way around control system problems? Concerned about getting ripped off again.

4 comment(s)


luisesilver8

Based on a similar situation with my 2012 Audi S4, the symptoms you describe align with main relay problems affecting the engine control unit. When automotive electronics fail this way, the ECU receives inconsistent power, leading to those reduced power symptoms and error codes. During vehicle electronics diagnostics, my situation revealed the main relay had deteriorated, causing intermittent ECU problems. The fix required replacing the main relay and recalibrating the engine control unit, not a quick repair but essential for proper engine performance. This is a serious issue that needs addressing by a qualified technician experienced with ECU repair. The symptoms worsen over time and can eventually prevent the car from starting altogether. While the main relay itself is a relatively simple part, the diagnostic process and ECU recalibration require specialized knowledge. Look specifically for shops that: Specialize in German vehicle electronics, Have certified diagnostic equipment for ECU problems, Can provide detailed documentation of testing procedures, Offer warranty on both parts and labor Getting a second diagnostic opinion is worthwhile given the complexity of modern automotive electronics systems and your previous experience with questionable repairs.

marioschneider68 (Author)

Thanks for that detailed explanation of the ECU and relay issues. Your expertise with automotive electronics really helped me understand what was happening with my car. The system reset and recalibration fixed the problem completely, and engine performance is back to normal. Quick question, do you remember roughly how much you paid for the entire control system repair? Also, has everything stayed working properly since the fix? I want to make sure I budget correctly and know what to expect long-term with my SQ5.

luisesilver8

Good news on the repair front. Just got the car back from the shop after dealing with similar ECU problems on my S4. The main relay replacement and control system recalibration cost 120 Euro total, which was reasonable considering the specialized ECU repair work involved. The vehicle electronics have performed flawlessly since the fix, no more engine performance issues or error codes. The engine control unit now functions exactly as it should, with proper power delivery and system response. For preventive maintenance, I recommend keeping an eye on your battery health since weak batteries can sometimes stress the ECU and related components. But with the faulty main relay replaced, you should be good for many years of trouble-free operation. The investment in proper ECU repair by a qualified technician definitely beats the headache of intermittent problems and potential roadside issues. Just make sure to keep your repair documentation in case any warranty matters come up.

marioschneider68 (Author)

Thanks for sharing the cost details. Just got back from my automotive electronics specialist and wanted to update. The whole repair came to 150 Euro, slightly more than yours but still worth every cent. The technician found the engine control unit needed a full system reset along with the relay replacement. Had a really different experience from my last mechanic. This shop actually showed me the diagnostic readings and explained the whole computer module repair process. No more check engine lights or power issues since the fix. Been driving for a week now and the car feels brand new, way better throttle response and smooth acceleration. Even my fuel economy improved a bit. Definitely learned my lesson about finding the right specialist for complex control system work rather than going to the cheapest option.

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