What P0121 Means for Your 2022 Cadillac XT6
A P0121 on your 2022 Cadillac XT6 indicates the ECM has detected an abnormal throttle position sensor signal pattern. The readings are within voltage specs but don't correlate with your pedal position—our detective has flagged a throttle body communication issue.
The 2022 XT6 offers a 2.0L turbocharged four-cylinder (DI) or a 3.6L V6 (port injection), both paired with a 9-speed automatic. The three-row luxury crossover demands smooth, predictable throttle response for passenger comfort. The 2.0T's direct injection makes it more carbon-prone than the V6.
Symptoms
- Check engine light and possible Reduced Engine Power
- Hesitation during acceleration, especially when loaded
- Idle roughness
- Throttle response inconsistency
- Sluggish feel with three rows of passengers
Causes Ranked
- Carbon buildup on throttle body – The 2.0T DI engine is the primary suspect. The V6's port injection is more resistant. Likelihood: 45%
- Throttle body assembly wear – Internal TPS or motor degradation. Likelihood: 25%
- ECM software update – GM calibration refinement. Likelihood: 15%
- Wiring or connector issue – Heat-related connector degradation. Likelihood: 10%
- Intake system leak – Turbo piping or intake gasket. Likelihood: 5%
Repair Costs
- Throttle body cleaning: $80–$180 (shop) / $10–$25 (DIY)
- Throttle body replacement: $300–$600 parts and labor
- ECM update: $100–$180 (dealer)
- Wiring repair: $100–$250
Warranty & DIY
Your 2022 XT6 should be within Cadillac's 4-year/50,000-mile bumper-to-bumper warranty depending on mileage, and the 6-year/70,000-mile powertrain warranty should apply. Take it to the dealer for free repair. If out of basic warranty, throttle body cleaning is moderate difficulty. Perform GM idle relearn after cleaning.
How AutoDetective AI Can Help
Upload your XT6's scan data to AutoDetective for an engine-specific AI diagnosis. Our system differentiates between the 2.0T and 3.6L V6 platforms.