What P0121 Means on a 2024 Buick Envision
A P0121 on your 2024 Buick Envision indicates the ECM has caught the throttle position sensor sending erratic signals. The data is within voltage limits but doesn't match expected behavior—our detective has flagged a communication breakdown between the throttle body and engine computer.
The 2024 Envision continues with the 2.0L turbocharged four-cylinder DI engine. On a vehicle this new, software calibration is the leading suspect, though the DI turbo engine's carbon tendencies can produce deposits even at low mileage with city driving patterns.
Symptoms
- Check engine light with possible Reduced Engine Power
- Hesitation on acceleration
- Idle quality diminished
- Turbo feels less responsive
- Throttle response inconsistency
Probable Causes
- ECM software calibration – GM continues releasing turbo engine throttle refinements. Likelihood: 35%
- Carbon deposits – DI turbo carbon accumulation from short trips. Likelihood: 30%
- Throttle body defect – Manufacturing quality issue. Likelihood: 20%
- Connector issue – Factory assembly problem. Likelihood: 10%
- Boost system anomaly – Wastegate or piping issue. Likelihood: 5%
Cost
- All repairs: $0 under warranty
- Out-of-warranty reference: Cleaning $80–$160, replacement $300–$550, software $100–$180
Take It to Buick
Your 2024 Envision is fully covered under GM's 3-year/36,000-mile and 5-year/60,000-mile powertrain warranty. Take it to the dealer for free repair via GDS2 diagnostics. No DIY needed on a warranted vehicle.
How AutoDetective AI Can Help
AutoDetective's AI analyzes your Envision's freeze frame data against known 2.0L turbo patterns. Upload your scan data for a free preliminary diagnosis.