What Does P0121 Mean on a 2022 Buick Encore GX?
A P0121 on your 2022 Buick Encore GX tells the ECM that the throttle position sensor signal isn't tracking correctly. The voltage reads within specs but the pattern is off—our detective has found a clue that the throttle body isn't faithfully reporting its position to the engine computer.
The 2022 Encore GX uses either a 1.2L turbocharged three-cylinder or a 1.3L turbocharged three-cylinder, both with direct injection. These small-displacement turbo engines rely heavily on precise throttle control for managing boost and fuel delivery. The compact engine bay means the throttle body sits in close proximity to the turbocharger's heat.
Symptoms
- Check engine light on
- Possible Reduced Engine Power message
- Hesitation or lag during acceleration
- Rough or hunting idle
- Engine may feel underpowered
Top Causes
- Carbon buildup on throttle body – The small DI turbo engines are particularly prone to carbon deposits. Short city commutes—the Encore GX's primary use case—make it worse. Likelihood: 50%
- Throttle body assembly issue – The compact throttle body's TPS or motor can develop faults. Likelihood: 20%
- ECM software update – GM may have released calibrations for the three-cylinder turbo engine's throttle management. Likelihood: 15%
- Wiring or connector corrosion – Turbo heat in the compact engine bay accelerates connector degradation. Likelihood: 10%
- Boost system interaction – Wastegate or bypass valve affecting throttle body pressure. Likelihood: 5%
Repair Costs
- Throttle body cleaning: $80–$150 (shop) / $10–$20 (DIY)
- Throttle body replacement: $250–$450 parts and labor
- ECM update: $100–$180 (dealer)
- Wiring repair: $100–$250
Warranty Check
Your 2022 Encore GX may still be within GM's 3-year/36,000-mile bumper-to-bumper warranty depending on purchase date. The 5-year/60,000-mile powertrain warranty should apply. If out of basic warranty, throttle body cleaning is moderate difficulty on the three-cylinder engine. After cleaning, perform GM's relearn: disconnect battery for 30 minutes, reconnect, idle for 15 minutes.
How AutoDetective AI Can Help
AutoDetective's AI understands the Encore GX's small-displacement turbo DI platform. Upload your scan data for a diagnosis tailored to the three-cylinder engine's specific patterns.