S3 PTC Heater Issues Causing Cold Start Headaches

Recently faced similar symptoms on my 2010 Audi A4 2.0T. The PTC heater failure caused significant cold start problems and increased fuel consumption. The temperature control system struggled to maintain proper engine operating temps. The main issue was the electric auxiliary heater had completely failed, preventing proper engine warm-up. This affected multiple systems since cold engines run less efficiently and require fuel enrichment. The blower motor was working overtime trying to compensate for the heating system deficiency. The repair required: Complete PTC heater assembly replacement, System diagnostic scan to clear fault codes, Testing of the new heating system components, Recalibration of temperature sensors This was a serious repair that needed immediate attention as continued operation could lead to: Further increased fuel consumption, Potential engine wear from extended cold running, Poor cabin heating performance, Risk of catalytic converter damage Would strongly recommend having it checked by an Audi specialist. The symptoms match exactly what happened with my A4, and postponing the repair only leads to additional problems.

Thanks for sharing your experience with the heater repair on your A4. Really useful info since my S3 seems to be showing identical cold start and heating issues. Quick question, do you remember roughly what you paid for the full fix? Also curious if any other electrical faults or heat not working issues came up since getting it repaired? My HVAC system is still acting up so trying to budget for potential additional repairs.

Good news on the repair front, the PTC heater replacement completely resolved all the heating issues. The total came to 350 Euro for fixing the defective electric auxiliary heater, which was actually less than expected for an Audi repair. Since the fix, the HVAC system has been working flawlessly. No more cold start problems, the engine warms up normally, and fuel consumption is back to standard levels. The blower motor now functions properly without having to overwork to compensate for the faulty heater. The investment was worth it as the heating system now maintains consistent temperature. No additional electrical faults have appeared in the months following the repair. The diagnostic codes cleared up and haven't returned, suggesting the PTC heater was indeed the root cause of the problems. If your symptoms match what I experienced, getting it fixed sooner rather than later could prevent more extensive damage to related components. The repair should resolve both the engine temperature management and cabin heating issues you described.

I finally got my S3 fixed last week after dealing with those cold start issues and high fuel consumption problems. Took it to a specialist shop that actually knew what they were talking about, what a difference from my last garage experience. The diagnosis confirmed what everyone suggested, the PTC heater was completely shot. The heating element had failed, causing all those cold start problems and making the HVAC system work overtime. The repair bill came to 380 Euro total, including parts and labor, which felt reasonable considering all the problems it was causing. Since the fix, the engine warms up properly, and the cold starts are smooth again. The blower motor isnt struggling anymore, and the heating system works like new. Fuel consumption has dropped back to normal levels too. Really glad I got it sorted before winter, no more sitting in a cold car waiting for the engine to warm up. Just wanted to close the loop and thank everyone for their help. If anyone else runs into similar issues, dont wait around like I did, getting it fixed promptly definitely saves money in the long run.