Audi Q3 Heat Failure, Valve Investigation

The symptoms you describe match what happened with my 2019 Audi Q5 2.0 TFSI. Initially thought it was a heater core issue, but diagnostics revealed a defective electronic valve control module for the heating system. The actual problem was a corroded plug connection at the climate control valve, which prevented proper communication between the control unit and the valve itself. This caused restricted coolant flow through the heater core, resulting in poor heating performance. This is a more common issue than many realize with these engines. The repair involved replacing the entire valve assembly as the connections were integrated. While not as serious as engine overheating concerns, it required removing several components to access the valve location. A proper diagnosis is crucial here, what seems like a simple automotive valve problem can be mistaken for various other issues like coolant leaks or heater core failures. Based on your description and the error code presence, the mechanic's valve diagnosis is likely correct. The repair took about 4 hours at the workshop, and resolving it promptly prevented any potential damage to related components.

Thanks for your detailed explanation about the valve issue. This really matches my symptoms. I also got it fixed last month and can confirm it was indeed the electronic valve control module causing restricted coolant flow to the heater core. Did you experience any other cooling system problems since the repair? Also curious about your repair costs, my bill came to 385 Euro parts and labor for the automotive valve replacement, wondering if that was in line with what you paid?

Since having the water valve defect fixed three months ago, my car heating system has worked flawlessly. The coolant flow is now properly regulated and I have not experienced any additional cooling system issues. The repair bill in my case was actually lower at 95 Euro since only the cable connection needed replacement rather than the entire automotive valve unit. The technician found the fault was specifically in the plug connection to the valve control module, which was a much simpler fix than replacing the complete assembly. This explains the significant cost difference compared to your repair. When these connections are caught early before corrosion spreads, it often prevents the need for more extensive repairs. If your valve required complete replacement, the 385 Euro cost seems reasonable given the labor involved in accessing and replacing the component. The important thing is that both our heating issues were properly diagnosed and fixed, preventing any risk of engine overheating or further damage to the cooling system.

Thanks everyone for sharing your experiences. After seeing all the replies, I went ahead and had my car checked out. Turned out my automotive valve was completely blocked, causing major coolant flow issues to the heater core. The mechanic found significant corrosion in the control module connections, similar to what others described. They ended up replacing the entire valve assembly since the damage was too extensive for a simple repair. Really glad I got it fixed before winter, the heating now works perfectly again. Total cost came to 440 Euro for parts and labor, bit more than expected but worth it to prevent any engine overheating issues down the line. The repair took about 5 hours since they had to remove several components to access the valve blockage area. Case closed on this one, appreciate all the helpful feedback that pointed me in the right direction.