What P0121 Means on a 2024 Volvo XC90
When your 2024 Volvo XC90 logs P0121, the ECM has caught the throttle position sensor sending inconsistent data. The signal is in range but the behavior is off—our detective's investigation focuses on the electronic throttle body.
The 2024 XC90 continues on the SPA platform with the 2.0L Drive-E in B5 (turbo, 247 hp) or B6 (turbo + supercharger, 295 hp) mild-hybrid configurations, plus the T8 Recharge PHEV. All use direct injection. On a new vehicle, software calibration leads the suspect list, with the DI engine's carbon tendency as a secondary factor.
Symptoms
- Check engine light on
- Hesitation on acceleration
- Idle roughness
- Boost transitions feel rough
- T8: engine-to-electric handoff inconsistency
Probable Causes
- ECM software calibration – Volvo regularly refines the SPA platform software. Likelihood: 40%
- Carbon deposits – DI engine carbon from short-trip driving. Likelihood: 25%
- Throttle body defect – Manufacturing quality issue. Likelihood: 20%
- Connector issue – Factory connection problem. Likelihood: 10%
- Boost system anomaly – Supercharger clutch or wastegate (B6/T8). Likelihood: 5%
Cost
- All repairs: $0 under warranty
- Out-of-warranty reference: Cleaning $120–$200, replacement $400–$700, software $100–$250
Volvo Dealer Service
Your 2024 XC90 is fully covered under Volvo's 4-year/50,000-mile bumper-to-bumper warranty. The dealer will use VIDA for complete diagnostics, software updates, and throttle body service at no cost.
How AutoDetective AI Can Help
Upload your scan data to AutoDetective for a free analysis tailored to your XC90's powertrain variant.