Audi A6 Air Conditioning Repair
When Mr J booked his Audi A6 in for its regular service at Fitch Autos in Brownhills, he mentioned that the air conditioning wasn’t keeping the cabin cool. During the service, our technicians confirmed that the refrigerant level was correct and the system was properly sealed, but the air conditioning still refused to cool.
With a re-gas ruled out, we arranged for Mr J to return for a diagnostic appointment so that our technicians could investigate further. Our team are experts in combining data analysis with specialist electrical testing to trace the root cause of any fault.
What followed highlighted the importance of precision and experience in modern diagnostics — the kind of expertise that ensures even complex faults can be identified with confidence.
Is your Audi A6 AC not working? Read on to see how our Brownhills team uncovered the real fault and brought the cool back.
Audi A6 AC Not Working: Where Our Diagnostic Process Began
Following his service, Mr J returned to Fitch Autos in Brownhills for a dedicated diagnostic appointment so our technicians could investigate why his Audi A6 AC wasn’t working. During the earlier checks, we had already confirmed that the refrigerant level was correct and that the system was holding pressure properly. Even so, the air conditioning still wouldn’t cool the cabin.
That told us the problem wasn’t mechanical but likely related to the system’s wiring. The first step was to carry out a full system scan using our dealer-level diagnostic tools. It flagged up one fault code:
- 00256 – Air Conditioning Pressure/Temperature Sensor (G395): No Signal/Communication
This part, the G395 pressure temperature sensor, is responsible for monitoring refrigerant pressure and temperature. It sends data to the control unit to regulate compressor function safely. If no signal is received, the system switches off the compressor to prevent possible damage, leaving no cool air being produced.
With the refrigerant system confirmed to be healthy, our technicians identified two main possibilities: a fault within the G395 sensor itself or a wiring defect causing a break in communication. The next stage was to carry out precise electrical testing to pinpoint exactly where the signal was being interrupted.
The Diagnostic Journey Continues
With the first tests complete, our next step was to find where communication between the G395 pressure temperature sensor and the vehicle’s control system had been lost.
Guided by Data and Experience
To pinpoint the problem, our technicians turned to Audi’s official wiring diagrams and workshop manuals. These are detailed technical maps showing how voltage, grounding, and communication lines link across the vehicle’s systems. By following the wiring path for the G395 sensor, we could see exactly how it connected to the control unit through a single communication wire.
Using an oscilloscope, which lets us view the live electrical signal, we checked the three wires at the sensor’s connector:
- Voltage supply: Correct and stable.
- Earth: Functioning properly with a strong return path.
- Signal wire: No communication detected.
This told us that the sensor had both voltage and ground but was unable to send data back to the control unit.
Confirming the Findings
To confirm this, we compared readings from another sensor running on the same communication circuit. Its signal was consistent and within expected parameters, proving the control module was working correctly. The issue, therefore, was somewhere between that connection point and the G395 pressure temperature sensor itself.
Tracing the Fault
Following the wiring route carefully, we tested continuity and signal quality at connection points throughout the circuit — from the control module to the front of the car. The signal remained strong up to a connector located behind the passenger-side trim. From there, the wiring runs over the nearside front wheel arch and beneath the headlamp.
Once the protective covering was carefully opened, the fault became visible. A section of wire had corroded within the main bundle, where moisture had entered the protective sleeve and damaged the copper strands. This corrosion had broken communication between the sensor and the control unit.
With the problem confirmed, we had found the cause of the Audi A6 air conditioning fault — a corroded wire interrupting the signal from the G395 pressure temperature sensor. The next step was to repair the damage and restore communication.
Repairing the Audi AC Wiring Fault
With the cause confirmed, our next task was to repair the damaged wiring and ensure the connection would remain protected against any future moisture ingress. Before starting the work, we contacted Mr J to explain our findings and outline the next steps. Once we had his approval, our technicians began the repair.
Accessing the Fault Area
The damaged wire had already been uncovered during the diagnostic process, when corrosion was found inside the protective sleeve that runs through the nearside front wheel arch and beneath the headlamp. With the area now open and secure, our technician prepared the section for repair, taking care to safeguard nearby wiring and insulation.
Repairing the Wiring
Following Audi’s wiring repair standards, our technician carried out the process step by step:
- Removed the corroded section of wire to expose clean copper on both sides.
- Installed a replacement length of automotive-grade wire with matching specification.
- Used professional crimp connectors with heat-sealed insulation to prevent future water ingress.
- Checked circuit continuity to confirm a strong, consistent connection.
Testing the Results
Once the repair was complete, the G395 pressure temperature sensor was reconnected, and the stored fault code cleared. Using the oscilloscope again, our technician confirmed that the communication signal was now stable and complete. The air conditioning compressor reactivated immediately, and cool air returned to the cabin. A final diagnostic scan confirmed that no further fault codes were present.
With communication restored and the Audi A6’s air conditioning system working as intended, Mr J’s car was ready to deliver reliable cooling once again.
A/C Fixed with Skill and Care
Mr J, was delighted with the result. The air conditioning in his Audi A6 was back to blowing cool, consistent air, restoring comfort and reliability on every drive. What started as a fault with no obvious cause ended with the system performing exactly as intended.
That outcome was made possible by the precision and care of our technicians at Fitch Autos in Brownhills. Using structured electrical testing and manufacturer-approved repair methods, they confirmed the problem and restored full communication between the G395 pressure temperature sensor and the vehicle’s control system.
This kind of accuracy takes more than experience — it relies on understanding how each signal and component works together and knowing how to prove the result through testing. Our technicians combined that expertise with practical, hands-on skill to deliver a repair that the customer could trust.
This case shows how careful diagnostics and methodical workmanship make all the difference. For complex systems like the Audi A6, getting it right first time means the driver can get back on the road with complete confidence.
Fitch Autos Are Experts in Complex Repairs
When the team at Fitch Autos in Brownhills investigated this detailed air conditioning fault, every stage of the repair process reflected our commitment to accuracy and quality. From diagnosing the electrical issue to restoring the system’s communication, each step was carried out with care and precision.
It’s this thorough, methodical approach that sets Fitch Autos apart. We take the time to test properly, confirm our results, and make sure every repair is completed to the highest standard. No guesswork, no quick fixes — just dependable workmanship and results you can trust.
Here’s what you can expect when you visit Fitch Autos:
- Accurate diagnostics and repairs completed to manufacturer standards
- Experienced technicians trained in modern vehicle electronics and diagnostics
- Access to the latest repair data and testing technology
- Honest, clear communication from start to finish
- 12-month parts and labour guarantee
- Courtesy cars available
We’re proud to be trusted by drivers across Brownhills, Aldridge, and Cannock, many of whom return year after year for professional servicing and reliable repairs.
We have a {{average-rating}} star Google rating from {{review-count}} satisfied customers, showing why so many local drivers choose us for expertise they can rely on.
If your Audi A6 AC isn’t working, call Fitch Autos in Brownhills today on 01543 452630. Our team will find the true cause of the problem and restore your system to full performance.
