Investigating P0121 on Your 2022 Buick Enclave
A P0121 on your 2022 Buick Enclave means the ECM has found an irregular throttle position sensor signal. The voltage is in range but doesn't match expected patterns—our detective has identified a discrepancy in the throttle body's communication that needs resolution.
The 2022 Enclave uses a 3.6L V6 with port fuel injection and a 9-speed automatic. As a GM-based vehicle, it shares its electronic throttle control system with other GM products. The port injection system naturally keeps the throttle body cleaner than direct-injection engines, but PCV vapor deposits still accumulate over time.
Symptoms
- Check engine light on
- Possible Reduced Engine Power message
- Hesitation during acceleration
- Rough or unstable idle
- Sluggish response, especially with passengers and cargo
Causes Ranked
- Carbon buildup on throttle body – PCV vapors coat the throttle plate over time. The Enclave's frequent use for family hauling means higher engine loads and more deposit formation. Likelihood: 45%
- Throttle body assembly wear – Internal TPS or motor degradation. Likelihood: 25%
- Wiring or connector corrosion – Engine bay heat degrades connectors. Likelihood: 15%
- ECM software update – GM calibration refinement for the Enclave's throttle management. Likelihood: 10%
- Intake vacuum leak – Cracked PCV hose or intake gasket. Likelihood: 5%
Repair Costs
- Throttle body cleaning: $80–$160 (shop) / $10–$20 (DIY)
- Throttle body replacement: $300–$550 parts and labor
- Wiring repair: $100–$250
- ECM update: $100–$180 (dealer)
Check Warranty First
Your 2022 Enclave 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 still apply. If out of warranty, throttle body cleaning is straightforward—the 3.6L V6's throttle body is accessible from the top. After cleaning, perform GM's idle relearn: disconnect the battery for 30 minutes, reconnect, then idle for 15 minutes undisturbed.
How AutoDetective AI Can Help
Upload your Enclave's scan data to AutoDetective for an AI diagnosis specific to the 3.6L V6 platform. Our system cross-references GM TSBs and known patterns to identify the most likely cause.