BRZ ECU Troubles: Performance Loss Warning Signs

Having experienced similar symptoms with my 2014 Toyota GT86 (essentially the same platform), I can share some relevant insights from my journey with ECU-related issues. The car diagnostics initially pointed to ECU problems, but after a thorough control system check, the workshop discovered a faulty main relay was causing intermittent power supply issues to the computer module. This created symptoms that mimicked a failing ECU. The repair process involved: 1. Complete vehicle electronics scan 2. Testing power supply to the ECU 3. Main relay replacement 4. ECU reset and adaptation Total cost was 120€ for parts and labor, which was far better than replacing the entire ECU. Before jumping to conclusions about ECU replacement, could you share: Which specific error codes are stored? Does the issue occur more frequently when the engine is hot or cold? Are there any other electrical symptoms like flickering lights or rough idle? Have you noticed any correlation with weather conditions? This information would help determine if your issue matches the relay problem I encountered or points to a different component in the engine control system.

Last serviced at 109227 KM, and I want to update everyone on my situation. After running the car diagnostics suggested, it turns out my engine control issues were linked to corroded ECU connectors rather than a complete computer module failure. The pins showed significant oxidation, affecting various engine performance parameters. I cleaned the connections thoroughly and applied dielectric grease. This resolved about 80% of the performance issues, but some error codes still persist. Currently weighing whether to proceed with a full ECU replacement or try another round of connection cleaning. Would really appreciate hearing from others who might have gone through the cleaning process multiple times, did it eventually solve all your engine control problems or was replacement ultimately necessary?

Thanks for the update on your BRZ's engine control issues. On my GT86, I also initially tried cleaning the ECU connectors which brought temporary improvement. However, after about 2-3 cleaning attempts over several months, the engine performance problems kept returning due to ongoing corrosion issues in the automotive electronics. The computer module connectors are particularly sensitive to environmental factors. While cleaning and applying dielectric grease can help, it often masks deeper connection problems within the vehicle electronics system. In my case, after the third cleaning attempt, I opted for the ECU replacement since the control system issues were affecting daily drivability. The full replacement cost was 890€ but resolved all performance problems permanently. The shop also installed additional connector protection to prevent future corrosion. Given your description of persistent error codes despite cleaning, this sounds very similar to what I experienced. While another cleaning might help temporarily, you may want to consider: 1. Having the entire connector assembly replaced 2. Upgrading to a sealed connector design 3. Full ECU replacement if problems continue Would be helpful to know which specific error codes remain after cleaning, this could indicate if you are dealing with the same progressive connector deterioration I encountered.

Thanks for the feedback. After careful analysis of the car diagnostics data and your experiences, I decided to address my BRZ issues systematically. The remaining error codes (P0606 and P0607) strongly suggest internal ECU problems beyond just connector corrosion. Following my third attempt at cleaning the connections, I noticed the engine control issues returning within just a few days. The performance drop was more severe each time, and the system reset only provided temporary relief. I scheduled an appointment with a specialist shop that focuses on ECU repair. They confirmed internal circuit board damage from the long-term corrosion exposure. The complete ECU replacement ended up costing 950€, but the engine control system is now functioning perfectly. All error codes are cleared and power delivery is back to normal. For others facing similar issues: while connector cleaning is worth trying initially, don't waste too much time if problems persist. The diagnostic evidence and multiple repair attempts clearly showed that band-aid solutions weren't going to provide a permanent fix for my compromised control system.