Tracking P0121 on Your 2022 Buick Envision
A P0121 on your 2022 Buick Envision means the ECM has detected abnormal throttle position sensor behavior. The TPS voltage stays within range but the signal pattern doesn't correlate with your accelerator pedal—our detective has spotted a discrepancy that points to the throttle body as the prime suspect.
The 2022 Envision is powered by a 2.0L turbocharged four-cylinder with direct injection producing 228 hp, paired with a 9-speed automatic. This engine uses GM's electronic throttle control with integrated dual TPS signals. The DI turbo engine is more susceptible to carbon-related throttle issues than naturally aspirated port-injection engines.
Symptoms
- Check engine light on
- Possible Reduced Engine Power
- Hesitation during acceleration
- Rough idle, especially with A/C on
- Turbo response feels diminished
Causes Ranked
- Carbon buildup on throttle body – The 2.0L turbo DI engine is prone to carbon deposits. City driving and short trips accelerate accumulation. Likelihood: 50%
- Throttle body assembly wear – Internal TPS or motor degradation at 2–4 years old. Likelihood: 20%
- ECM software update – GM calibration refinement for the Envision's turbo throttle management. Likelihood: 15%
- Wiring or connector corrosion – Turbo heat accelerating connector degradation. Likelihood: 10%
- Boost or intake leak – Loose intercooler piping or intake boot. Likelihood: 5%
Repair Costs
- Throttle body cleaning: $80–$160 (shop) / $10–$20 (DIY)
- Throttle body replacement: $300–$550 parts and labor
- ECM update: $100–$180 (dealer)
- Wiring repair: $100–$250
Warranty & DIY
Check if your 2022 Envision is still within GM's 3-year/36,000-mile bumper-to-bumper warranty. The 5-year/60,000-mile powertrain warranty should still apply. If out of basic warranty, throttle body cleaning is moderate difficulty. After cleaning, perform GM's idle relearn: disconnect battery 30 minutes, reconnect, idle 15 minutes undisturbed.
How AutoDetective AI Can Help
AutoDetective's AI understands the Envision's 2.0L turbo DI platform. Upload your scan data for a free diagnosis that differentiates carbon buildup from sensor failure.