P0121 on Your 2022 Lexus ES: What's Going On?
When your 2022 Lexus ES sets a P0121, the ECM has detected that the throttle position sensor signal doesn't follow the expected pattern. The voltage is in range but behaves erratically—like a detective noticing that a witness's demeanor doesn't match their testimony. The throttle body is the focus of this investigation.
The 2022 ES comes as the ES 250 (2.5L four-cylinder), ES 350 (3.5L V6 with D-4S dual injection), or ES 300h hybrid (2.5L with hybrid system). The ES 350's D-4S system combines port and direct injection, which helps keep the throttle body and intake valves cleaner than DI-only engines. The ES 250 and 300h use simpler naturally aspirated configurations.
What Symptoms to Expect
- Check engine light illuminated
- Subtle hesitation during gentle acceleration
- Idle quality slightly degraded from Lexus-smooth standards
- Throttle response may feel inconsistent
- Possible slight surging at low speeds
Causes Ranked by Probability
- Carbon deposits on throttle body – PCV system vapors gradually coat the throttle plate and bore. The ES's typical gentle driving style means less wide-open throttle cleaning effect. Likelihood: 40%
- Throttle body assembly wear – Internal TPS sensor or motor degradation. Likelihood: 25%
- Wiring or connector corrosion – Age and engine bay heat can degrade the throttle body connector. Likelihood: 15%
- ECM software update – Toyota/Lexus releases periodic recalibrations for throttle parameters. Likelihood: 10%
- Air intake leak – Cracked intake resonator or loose air duct connection. Likelihood: 10%
Estimated Repair Costs
- Throttle body cleaning: $100–$180 (shop) / $10–$25 (DIY)
- Throttle body replacement: $350–$600 parts and labor
- Wiring repair: $100–$250
- ECM recalibration: $100–$200 (dealer)
Check Warranty First
Your 2022 ES may still be within Lexus's 4-year/50,000-mile basic warranty depending on purchase date and mileage. If covered, take it to the Lexus dealer for a no-cost repair. If out of warranty, throttle body cleaning is a moderate DIY job. After cleaning, perform a throttle relearn: disconnect the battery for 30 minutes, reconnect, then idle in Park for 10–15 minutes without touching the accelerator.
How AutoDetective AI Can Help
AutoDetective's AI analyzes your 2022 ES's specific powertrain configuration and mileage to rank the most likely causes. Upload your scan data for a free personalized diagnosis.