Audi Q7 Cold Start Issues Point to PTC Heater Fault

I dealt with a very similar issue on my 2018 Audi Q5, and having some experience with these types of problems, I can share what worked for me. The symptoms were exactly as you describe, rough cold starts and the HVAC system not performing optimally. The heating element, specifically the electric auxiliary heater, was diagnosed as faulty during a workshop inspection. The cold air coming through the vents was a clear indication something was wrong with the heater repair components. The workshop performed a full diagnostic scan which confirmed issues with the PTC (Positive Temperature Coefficient) heater. They found the heating system was not receiving proper power, causing the auxiliary heating function to fail. The repair involved replacing the complete PTC heater unit, costing 350 Euro including labor. This fixed both the cold start issues and restored proper heating functionality. Fuel consumption returned to normal levels as well. To provide more specific advice for your case, could you share: Current mileage on your Q7, Whether you notice any unusual sounds from the heating system, If the check engine light shows constantly or intermittently, Which specific fault code you received These details would help determine if your issue matches what I experienced and whether the same solution might apply.

Last service was at 28855 KM and the fault code appeared shortly after. Just wanted to thank everyone for their input. After bringing it to the workshop, they confirmed the temperature control unit was malfunctioning, affecting both engine performance and the HVAC system. The technician found the heating element had indeed failed, causing the cold air issues and poor cold starts. They replaced the PTC heater and recalibrated the system. Total repair cost was 380 Euro. The engine now runs smoothly from cold starts and heating works perfectly. Fuel consumption is back to normal too.

This matches exactly what I experienced with my Q5. It's good to hear the fix was similar and relatively straightforward. The symptoms and repair costs align closely with what I encountered, my repair was 350 Euro compared to your 380 Euro, which seems reasonable given the time difference and model variation. The relationship between the electrical fault in the PTC heater and engine performance issues during cold starts is a known weakness in these models. The blower motor and temperature control systems are quite interconnected with engine management, which explains why a faulty heating element can cause multiple symptoms. For anyone else reading who might experience similar issues: watch for increased fuel consumption and poor cold starts as early warning signs. These symptoms, combined with heating problems, often point to a failing PTC heater in the HVAC system. Getting it diagnosed early can prevent additional strain on related components. Your mileage being relatively low when the issue occurred (28855 KM) is interesting, mine failed at around 32000 KM, suggesting this might be a common failure point for this component.

Thanks for all the help with diagnosing my Audi's issues. Really appreciate confirming what I suspected about the heating system problems. After the workshop replaced the PTC heater and recalibrated everything, the cold start problems completely disappeared. The temperature control now works flawlessly and no more issues with high fuel consumption. The total repair of 380 Euro was money well spent considering how much better the car runs now. For anyone searching the forums with similar symptoms, if you notice poor cold starts and heating issues, definitely get the PTC heater checked. The fault codes and increased fuel consumption were clear indicators in my case. Really glad I addressed it promptly before it could cause any additional problems. The car feels like new again with proper heat working and smooth cold starts. Will update if anything changes, but so far the fix seems to have completely resolved both the engine and heating system issues. Thanks again for helping point me in the right direction with the diagnosis.