Investigating P0121 on Your 2022 Cadillac XT5
A P0121 on your 2022 Cadillac XT5 tells the ECM that the throttle position sensor signal is behaving erratically within its expected voltage range. Our detective has identified a clue—the throttle body isn't accurately reporting its position to the engine computer.
The 2022 XT5 uses either a 2.0L turbocharged four-cylinder with direct injection (237 hp) or a 3.6L V6 with port injection. The turbo four is more susceptible to carbon-related throttle issues due to its DI fuel system, while the V6's port injection keeps the throttle body naturally cleaner.
Symptoms
- Check engine light on
- Possible Reduced Engine Power message
- Hesitation during acceleration
- Idle roughness
- Throttle response inconsistency
Causes Ranked
- Carbon buildup on throttle body – The 2.0L turbo DI model is particularly prone. The 3.6L V6 accumulates deposits more slowly. Likelihood: 45%
- Throttle body assembly wear – Internal TPS or motor degradation. Likelihood: 25%
- ECM software update – GM calibration refinement. Likelihood: 15%
- Wiring or connector corrosion – Engine bay heat effects. Likelihood: 10%
- Intake air leak – Cracked intake boot or loose turbo piping (2.0T). 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 Status
Your 2022 XT5 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 definitely apply. Contact your Cadillac dealer for free diagnosis and repair. If out of basic warranty, throttle body cleaning is moderate DIY difficulty. After cleaning, disconnect the battery 30 minutes, then idle 15 minutes to reset GM throttle adaptations.
How AutoDetective AI Can Help
AutoDetective's AI differentiates between the XT5's 2.0T and 3.6L V6 to rank causes specific to your engine. Upload your scan data for a free diagnosis.