Understanding P0121 on the 2024 Audi Q5
A P0121 code on your 2024 Audi Q5 indicates the ECM has detected abnormal throttle position sensor behavior. The signal voltage is within range but the pattern is off—our detective's evidence suggests a throttle body communication issue that warrants further investigation.
The 2024 Q5 continues with the 2.0L TFSI (EA888) producing 261 hp with Quattro AWD. The Q5 PHEV adds electric assistance to the same base engine. As the final year of this Q5 generation before the 2025 redesign, this platform is well-refined but the DI engine's carbon susceptibility remains.
Symptoms
- Check engine light and EPC light
- Hesitation on acceleration
- Idle roughness
- Turbo response diminished
- Possible reduced power mode
Probable Causes
- ECM software calibration – Final model year updates for throttle and boost management. Likelihood: 35%
- Carbon deposits on throttle body – DI turbo engine carbon accumulation from short-trip driving. Likelihood: 30%
- Throttle body defect – Manufacturing quality issue. Likelihood: 20%
- Connector or wiring issue – Factory assembly problem. Likelihood: 10%
- Boost system interaction – Diverter valve or wastegate anomaly. Likelihood: 5%
Cost to Fix
- All repairs: $0 under warranty
- Out-of-warranty reference: Cleaning $100–$200, replacement $400–$700, software $100–$250
Take It to Audi
Your 2024 Q5 is fully covered under Audi's 4-year/50,000-mile warranty. The dealer will use ODIS to perform throttle body diagnostics, adaptation, and software updates—all at no cost. Do not attempt DIY on a warranted vehicle.
How AutoDetective AI Can Help
AutoDetective's AI cross-references Audi Q5 TSBs and EA888-specific failure patterns. Upload your scan data for a free preliminary diagnosis before your dealer appointment.