SQ8 Trans Failure Linked to Cooling System Malfunction

Had similar symptoms on my 2019 Audi S7. The transmission issues and warning lights turned out to be connected to a failing oil cooler system. After extensive leak detection tests, the problem was traced to damaged wiring and corroded plug connections between the transmission control module and cooling fan assembly. The cooling system was losing pressure due to these faulty connections, which made the transmission overheat and trigger the emergency mode. This created a chain reaction affecting multiple systems. The transmission temperature sensor was getting incorrect readings, causing the erratic gear shifts and grinding sounds. This is a serious issue that requires immediate attention since continued driving can lead to complete transmission failure. The repair involved replacing the wiring harness, installing a new transmission control module, and performing a complete system reset. The defective connections had also caused minor damage to the radiator repair points, which needed reinforcement. A qualified Audi specialist should perform proper diagnostic testing focusing on the cooling system pressure and transmission control module connections. Car overheating symptoms in these models often trace back to electrical issues rather than mechanical failures.

Thanks for sharing your S7 experience. Your case sounds exactly like what I am dealing with on my SQ8. A faulty cooling system definitely seems to match these transmission symptoms. Can you remember what the total repair cost was for fixing the pressure sensor and wiring issues? Also curious if you have had any coolant leak problems or other related issues since the repair was done?

Thanks for asking about the follow-up experience. After getting the wiring and plug connections fixed on the transmission control module, all the cooling system pressure issues cleared up completely. The total cost was surprisingly reasonable at 95 Euro since it turned out to be just faulty electrical connections rather than a major mechanical problem. The car has been running perfectly for the past 8 months with no coolant leaks or transmission problems. The radiator coolant pressure readings are now stable, and the transmission shifts smoothly without any warning lights. Having a proper diagnosis made all the difference, what seemed like a potential transmission replacement ended up being a straightforward electrical fix. The oil cooler and overall cooling system are working as they should, with no overheating issues whatsoever. Regular pressure checks show everything is maintaining proper levels. This experience taught me that car overheating and transmission problems often stem from simple electrical faults rather than major mechanical failures.

After getting such helpful advice, I decided to take my SQ8 to a certified Audi specialist rather than returning to my previous mechanic. The diagnostic testing revealed exactly what was suspected, faulty wiring connections affecting the cooling fan system and transmission control module. The pressure gauge readings confirmed inconsistent cooling system operation. They found corroded plugs and damaged wiring similar to what you described. The total repair came to 850 Euro, which included replacing the wiring harness, installing a new pressure sensor, and performing a full system reset. The radiator repair points also needed some work due to minor damage from the overheating. It has been 2 weeks since the fix, and the transmission is shifting perfectly with no warning lights or emergency mode issues. The cooling system is maintaining proper pressure, and all temperature readings are normal. I am relieved it was not a complete transmission failure requiring replacement. Sometimes getting a second opinion from the right specialist makes all the difference. The car runs like new again.