1. What is P0390 in Audi Q3?

The P0390 OBD-II code stands for Camshaft Position Sensor B Circuit Range/Performance (Bank 2). For the Audi Q3 45 TFSI (2019-2024)—a top-selling European compact luxury SUV with strong consumer demand—it targets the exhaust camshaft position sensor (Bank 2, Sensor 2) in its 2.0T EA888 Gen4 engine, standard in Premium, S line, and RS Q3 trims (paired with 7-speed S tronic transmission).

The EA888 Gen4 engine uses dual camshaft position sensors (intake: G40; exhaust: G163) per bank to sync valve timing with crankshaft rotation. Bank 2 refers to the second cylinder bank, and Sensor B denotes the exhaust-side unit. The sensor sends a 0.3–1.0V AC signal to the ECU—P0390 triggers when the signal falls outside the acceptable range (too high/low) or shows inconsistent performance for 3+ seconds.

Audi Q3 Specific Note: This code is widespread in 2020-2023 Q3 45 TFSI S line models, per Audi Technical Service Bulletin (TSB) 22-06-04. The EA888 Gen4’s exhaust camshaft sensor (#06K906433A) uses a Hall-effect design sensitive to thermal stress—frequent high-temperature driving (e.g., mountain roads, towing) degrades the sensor’s internal components, causing signal range issues that trigger P0390.

2. Common Causes of P0390 in 2019-2024 Q3

P0390 in Audi Q3 EA888 Gen4 models stems from camshaft sensor range/performance issues—below are real-world cases diagnosed with the ICARZONE UR800:

• Sensor Thermal Degradation (2022 Q3 S line): An owner with 45,000 miles reported reduced acceleration. The UR800’s Camshaft Sensor Signal Range Test showed signal voltage <0.2V (normal: 0.3–1.0V). Replacing the sensor with OEM #06K906433A (per TSB 22-06-04) fixed P0390.
• Wiring Harness Damage (2021 Q3 Premium): A Premium trim owner’s P0390 reappeared after off-road use. The UR800’s Circuit Continuity Test detected signal interruption (open circuit). Repairing frayed wires near the front bumper bracket resolved the range issue.
• ECU Calibration Drift (2023 Q3 45 TFSI): A 2023 Q3 owner’s P0390 triggered after a software update. The UR800’s ECU Signal Threshold Check showed incorrect calibration (0.4–0.9V instead of 0.3–1.0V). Recalibrating via UR800 fixed the range mismatch.
• Oil Sludge Buildup (2019 Q3 RS Q3): An RS Q3 owner’s P0390 occurred with engine ticking. The UR800’s Sensor Inspection Tool revealed sludge covering the sensor tip. Cleaning the sensor and replacing engine oil fixed signal performance.

3. Key Symptoms of P0390 in EA888 Gen4

P0390 symptoms in the Audi Q3 focus on valve timing misalignment and engine performance—watch for these signs that signal sensor range/performance issues:

4. Q3 Trims/Engines Prone to P0390

Audi service data highlights these 2019-2024 Q3 configurations with the highest P0390 occurrence rates (all EA888 Gen4 engines):

5. Diagnose P0390 with ICARZONE UR800

Diagnose P0390 in your Audi Q3 EA888 Gen4 accurately with the UR800’s Audi-specific camshaft sensor tools. Follow these steps (engine at operating temperature; battery voltage 12.4–12.7V):

Case Example: A 2022 Q3 S line failed Step 2 (0.18V) and Step 5 (TSB 22-06-04 eligible). The UR800’s Component Location Tool guided sensor access (driver-side cylinder head, rear of the engine bay). Replacing the degraded sensor restored signal to 0.6V—P0390 cleared, and acceleration performance improved by 15%.

6. How to Fix P0390 in Audi Q3

Resolve P0390 in your Q3 with these UR800-verified solutions—tailored to the EA888 Gen4’s camshaft sensor system:

1. Replace Exhaust Camshaft Sensor (Most Common Fix for TSB 22-06-04)

1. Confirm thermal degradation via UR800’s Step 2. Disconnect the negative battery terminal and remove the engine cover (4 Torx T30 screws).
2. Locate Bank 2 Sensor 2: Driver-side cylinder head, rear of the engine bay, with a 3-pin electrical connector (labeled "G163" on the harness).
3. Disconnect the connector (press the orange release tab) and remove the sensor (1 Torx T25 screw). Inspect for heat damage (discoloration, cracked housing).
4. Install an OEM exhaust camshaft sensor:
   • 2019-2021 Q3: #06K906433A
   • 2022-2024 Q3: #06K906433B (heat-resistant housing)
   Torque the sensor to 6 ft-lbs (use a torque wrench) to avoid damaging the threads.
5. Reconnect the connector and battery. Use UR800 to retest signal range (0.3–1.0V). Clear P0390 and test drive—confirm smooth acceleration and no misfires.

2. Repair Wiring Harness (for Continuity Interruptions)

1. Confirm wiring damage via UR800’s Step 3. Trace the sensor harness from the sensor to the ECU (passenger-side firewall). Look for frayed insulation, cuts, or corrosion near brackets.
2. Cut the damaged wire section (use wire cutters) and strip 1/4 inch of insulation from both ends. Splice with heat-shrink butt connectors (#Dorman 84715) rated for high temperatures.
3. Crimp the connectors with a wire crimper, then apply heat to seal (ensure no exposed copper). Wrap the repaired section with heat-resistant tape (#3M 33+).
4. Secure the harness to the engine bay bracket with zip ties—prevents contact with hot components. Reconnect the sensor connector.
5. Use UR800 to retest continuity (no interruptions). Clear P0390 and test drive on rough terrain—verify no signal drops.

3. Recalibrate ECU (for Signal Threshold Drift)

1. Confirm calibration drift via UR800’s Step 4. Connect UR800 to the OBD-II port (under the steering wheel) and turn the key to "ON."
2. Select "ECU" > "Calibration" > "Camshaft Sensor Signal Threshold." The UR800 will load the factory default range (0.3–1.0V) for the EA888 Gen4 engine.
3. Initiate the calibration process (takes 10–15 minutes). Do not turn off the key or disconnect UR800 during the procedure.
4. Once complete, use UR800 to verify the new threshold matches the target range. Test the sensor signal in live data mode.
5. Clear P0390 with UR800 and test acceleration—ensure the engine maintains consistent power without hesitation.

7. P0390 Repair Costs & Maintenance Tips

P0390 repair costs for the Audi Q3 EA888 Gen4 vary by cause. Use this table to budget:

Maintenance Tips for Q3 Owners

• Q3 S line (2020-2023): Replace the exhaust camshaft sensor every 50,000 miles (preventive) — use OEM #06K906433B for 2022+ models to comply with TSB 22-06-04 and avoid P0390.
• Premium trim owners (off-road enthusiasts): Inspect the sensor wiring harness every 20,000 miles—protect with conduit tubing to prevent damage from debris.
• Recalibrate the ECU via UR800 every 18 months—prevents signal threshold drift that triggers false P0390 codes in 2022+ Q3 models.
• Use Audi-approved 5W-40 synthetic engine oil and replace every 7,500 miles—reduces sludge buildup that clogs the sensor tip in RS Q3 models.
• Perform the UR800’s Camshaft Sensor Range Check every 12,000 miles — monitor signal stability and wiring integrity to catch issues before P0390 triggers.

8. Q3-Specific FAQs