Audi A5 AC Failure Linked to Faulty Temp Sensor

As someone with moderate experience working on cars, I had a similar issue with my 2014 Audi A4 2.0T last summer. The HVAC system completely failed, showing error messages on the dashboard. Initially, I thought it was just a temperature sensor, but after taking it to a workshop, they diagnosed a faulty air conditioning control unit. The cooling system diagnostic revealed that the control unit was not properly communicating with other components in the heat exchanger system. The workshop had to replace the entire AC control unit to restore proper functionality to the HVAC system. The repair took about 4-5 hours and cost 980 Euro including parts and labor. Since the fix, the air conditioning has worked flawlessly and all error codes cleared up. The temperature sensor readings returned to normal, and the entire cooling system now operates as intended. Before suggesting specific solutions for your A5, could you provide: Current mileage, Any unusual sounds from the HVAC system, Whether the air blows but isnt cold, or doesnt blow at all, The specific error codes from your diagnostic scan, Any previous AC repairs or maintenance history This information would help determine if your issue matches what I experienced with my A4.

As someone with moderate experience working on cars, I had a similar issue with my 2014 Audi A4 2.0T last summer. The HVAC system completely failed, showing error messages on the dashboard. Initially, I thought it was just a temperature sensor, but after taking it to a workshop, they diagnosed a faulty air conditioning control unit. The cooling system diagnostic revealed that the control unit was not properly communicating with other components in the heat exchanger system. The workshop had to replace the entire AC control unit to restore proper functionality to the HVAC system. The repair took about 4-5 hours and cost 980 Euro including parts and labor. Since the fix, the air conditioning has worked flawlessly and all error codes cleared up. The temperature sensor readings returned to normal, and the entire cooling system now operates as intended. Before suggesting specific solutions for your A5, could you provide: Current mileage, Any unusual sounds from the HVAC system, Whether the air blows but isnt cold, or doesnt blow at all, The specific error codes from your diagnostic scan, Any previous AC repairs or maintenance history This information would help determine if your issue matches what I experienced with my A4.

As someone with moderate experience working on cars, I had a similar issue with my 2014 Audi A4 2.0T last summer. The HVAC system completely failed, showing error messages on the dashboard. Initially, I thought it was just a temperature sensor, but after taking it to a workshop, they diagnosed a faulty air conditioning control unit. The cooling system diagnostic revealed that the control unit was not properly communicating with other components in the heat exchanger system. The workshop had to replace the entire AC control unit to restore proper functionality to the HVAC system. The repair took about 4-5 hours and cost 980 Euro including parts and labor. Since the fix, the air conditioning has worked flawlessly and all error codes cleared up. The temperature sensor readings returned to normal, and the entire cooling system now operates as intended. Before suggesting specific solutions for your A5, could you provide: Current mileage, Any unusual sounds from the HVAC system, Whether the air blows but isnt cold, or doesnt blow at all, The specific error codes from your diagnostic scan, Any previous AC repairs or maintenance history This information would help determine if your issue matches what I experienced with my A4.

Last service was 2 months ago at 197395 KM. Thanks for sharing your experience. After checking the fault codes again, I discovered the temperature sensor shows inconsistent readings compared to the actual coolant temperature. The heat exchanger seems to be working normally, but the sensor calibration appears off, causing the system to misread temperatures. The air still blows, but the cooling system struggles to maintain consistent temperature. No unusual sounds from the HVAC. During the diagnostic, the workshop found code P0118 related to the engine coolant temperature sensor circuit. The temperature gauge also fluctuates erratically while driving. Given these symptoms differ from your control unit issue, Im leaning toward a simpler sensor replacement. Still concerned about potential coolant leaks though, as the reservoir level seems slightly lower than usual. Would a sensor replacement alone likely resolve these symptoms, or should I expect additional repairs?

Last service was 2 months ago at 197395 KM. Thanks for sharing your experience. After checking the fault codes again, I discovered the temperature sensor shows inconsistent readings compared to the actual coolant temperature. The heat exchanger seems to be working normally, but the sensor calibration appears off, causing the system to misread temperatures. The air still blows, but the cooling system struggles to maintain consistent temperature. No unusual sounds from the HVAC. During the diagnostic, the workshop found code P0118 related to the engine coolant temperature sensor circuit. The temperature gauge also fluctuates erratically while driving. Given these symptoms differ from your control unit issue, Im leaning toward a simpler sensor replacement. Still concerned about potential coolant leaks though, as the reservoir level seems slightly lower than usual. Would a sensor replacement alone likely resolve these symptoms, or should I expect additional repairs?

Last service was 2 months ago at 197395 KM. Thanks for sharing your experience. After checking the fault codes again, I discovered the temperature sensor shows inconsistent readings compared to the actual coolant temperature. The heat exchanger seems to be working normally, but the sensor calibration appears off, causing the system to misread temperatures. The air still blows, but the cooling system struggles to maintain consistent temperature. No unusual sounds from the HVAC. During the diagnostic, the workshop found code P0118 related to the engine coolant temperature sensor circuit. The temperature gauge also fluctuates erratically while driving. Given these symptoms differ from your control unit issue, Im leaning toward a simpler sensor replacement. Still concerned about potential coolant leaks though, as the reservoir level seems slightly lower than usual. Would a sensor replacement alone likely resolve these symptoms, or should I expect additional repairs?

Thanks for providing those details. Your symptoms do sound different from my control unit failure, especially with that P0118 code and the temperature fluctuations. After dealing with my A4s issues, I learned these cooling system problems can be tricky to diagnose. Based on the erratic temperature readings and coolant level changes you mentioned, a malfunctioning temperature sensor is likely the primary issue. When I researched my own HVAC system problems, I found that faulty sensors often cause the heat exchanger system to operate inefficiently, leading to those inconsistent temperature readings youre experiencing. The vehicle maintenance records you shared showing recent service is helpful. Since no major cooling system work was done then, and the symptoms appeared afterward, this reinforces the sensor theory rather than a larger system failure. The repair should be relatively straightforward, much simpler than my control unit replacement. A temperature sensor replacement typically runs 150-200 Euro for parts and labor, significantly less than the 980 Euro I paid for my repair. Before proceeding, have the workshop pressure test the cooling system to rule out any leaks. While the sensor is the likely culprit, its worth checking the entire cooling circuit given the slight drop in coolant level you noticed.

Thanks for providing those details. Your symptoms do sound different from my control unit failure, especially with that P0118 code and the temperature fluctuations. After dealing with my A4s issues, I learned these cooling system problems can be tricky to diagnose. Based on the erratic temperature readings and coolant level changes you mentioned, a malfunctioning temperature sensor is likely the primary issue. When I researched my own HVAC system problems, I found that faulty sensors often cause the heat exchanger system to operate inefficiently, leading to those inconsistent temperature readings youre experiencing. The vehicle maintenance records you shared showing recent service is helpful. Since no major cooling system work was done then, and the symptoms appeared afterward, this reinforces the sensor theory rather than a larger system failure. The repair should be relatively straightforward, much simpler than my control unit replacement. A temperature sensor replacement typically runs 150-200 Euro for parts and labor, significantly less than the 980 Euro I paid for my repair. Before proceeding, have the workshop pressure test the cooling system to rule out any leaks. While the sensor is the likely culprit, its worth checking the entire cooling circuit given the slight drop in coolant level you noticed.

Thanks for providing those details. Your symptoms do sound different from my control unit failure, especially with that P0118 code and the temperature fluctuations. After dealing with my A4s issues, I learned these cooling system problems can be tricky to diagnose. Based on the erratic temperature readings and coolant level changes you mentioned, a malfunctioning temperature sensor is likely the primary issue. When I researched my own HVAC system problems, I found that faulty sensors often cause the heat exchanger system to operate inefficiently, leading to those inconsistent temperature readings youre experiencing. The vehicle maintenance records you shared showing recent service is helpful. Since no major cooling system work was done then, and the symptoms appeared afterward, this reinforces the sensor theory rather than a larger system failure. The repair should be relatively straightforward, much simpler than my control unit replacement. A temperature sensor replacement typically runs 150-200 Euro for parts and labor, significantly less than the 980 Euro I paid for my repair. Before proceeding, have the workshop pressure test the cooling system to rule out any leaks. While the sensor is the likely culprit, its worth checking the entire cooling circuit given the slight drop in coolant level you noticed.

This sensor issue definitely seems less severe than your control unit problem. After reviewing the P0118 code and temperature gauge behavior more closely, I feel more confident its primarily a sensor malfunction rather than a major cooling system failure. The consistent air flow without strange noises is also reassuring. The difference in symptoms between our cases makes sense, your control unit issue affected the entire HVAC operation, while my problems appear isolated to temperature sensing. Since my coolant level drop is minimal and the heat exchanger works normally, a simple sensor replacement should resolve the erratic readings. I appreciate the suggestion about pressure testing the cooling system first. Will have the workshop check for leaks before replacing the sensor. The 150-200 Euro estimate for the repair is much more manageable than I initially feared. Going to schedule the sensor replacement next week and will make sure they verify proper calibration afterward. The vehicle maintenance schedule shows the original sensor was never replaced, so it seems reasonable it could be failing after 7 years of operation. Thanks for helping me better understand these temperature-related issues.

This sensor issue definitely seems less severe than your control unit problem. After reviewing the P0118 code and temperature gauge behavior more closely, I feel more confident its primarily a sensor malfunction rather than a major cooling system failure. The consistent air flow without strange noises is also reassuring. The difference in symptoms between our cases makes sense, your control unit issue affected the entire HVAC operation, while my problems appear isolated to temperature sensing. Since my coolant level drop is minimal and the heat exchanger works normally, a simple sensor replacement should resolve the erratic readings. I appreciate the suggestion about pressure testing the cooling system first. Will have the workshop check for leaks before replacing the sensor. The 150-200 Euro estimate for the repair is much more manageable than I initially feared. Going to schedule the sensor replacement next week and will make sure they verify proper calibration afterward. The vehicle maintenance schedule shows the original sensor was never replaced, so it seems reasonable it could be failing after 7 years of operation. Thanks for helping me better understand these temperature-related issues.

This sensor issue definitely seems less severe than your control unit problem. After reviewing the P0118 code and temperature gauge behavior more closely, I feel more confident its primarily a sensor malfunction rather than a major cooling system failure. The consistent air flow without strange noises is also reassuring. The difference in symptoms between our cases makes sense, your control unit issue affected the entire HVAC operation, while my problems appear isolated to temperature sensing. Since my coolant level drop is minimal and the heat exchanger works normally, a simple sensor replacement should resolve the erratic readings. I appreciate the suggestion about pressure testing the cooling system first. Will have the workshop check for leaks before replacing the sensor. The 150-200 Euro estimate for the repair is much more manageable than I initially feared. Going to schedule the sensor replacement next week and will make sure they verify proper calibration afterward. The vehicle maintenance schedule shows the original sensor was never replaced, so it seems reasonable it could be failing after 7 years of operation. Thanks for helping me better understand these temperature-related issues.