What P0121 Tells You About Your 2022 Acura TLX
When your 2022 Acura TLX logs a P0121, the ECM has found that the throttle position sensor signal pattern is abnormal. The voltage is within expected limits, but the data doesn't properly track your accelerator pedal input—our investigation into the throttle system begins here.
The 2022 TLX is available with a 2.0L VTEC turbocharged four-cylinder (272 hp) or the Type S's 3.0L twin-turbo V6 (355 hp). Both engines use direct injection and electronic throttle control. The DI fuel system on both powertrains makes them more susceptible to carbon-related throttle issues. The Type S shares its powertrain with the MDX Type S.
Symptoms You'll Detect
- Check engine light on
- Hesitation or stumble during acceleration
- Idle may feel rougher than expected
- Throttle response inconsistency
- Possible turbo lag that seems abnormal
Top Causes
- Carbon buildup on throttle body – Both the 2.0L and 3.0L turbo engines use direct injection only, making them prone to carbon deposits on the throttle plate. Likelihood: 45%
- Throttle body assembly issue – Internal TPS sensor or actuator motor degradation. Likelihood: 25%
- ECM software update – Honda/Acura releases calibration updates for the TLX platform. Likelihood: 15%
- Wiring or connector problem – Heat and vibration degrading the throttle body connector. Likelihood: 10%
- Boost/intake leak – Loose turbo piping or intercooler connection. Likelihood: 5%
Repair Cost Estimates
- Throttle body cleaning: $100–$180 (shop) / $10–$25 (DIY)
- Throttle body replacement: $350–$650 parts and labor
- Wiring repair: $100–$250
- ECM update: $100–$200 (dealer)
Check Your Warranty
Your 2022 TLX may still be within Acura's 4-year/50,000-mile basic warranty depending on mileage. The 6-year/70,000-mile powertrain warranty should apply. Contact your Acura dealer first. If out of basic warranty, throttle body cleaning is moderate difficulty. After cleaning, perform Honda's idle relearn: key ON for 10 seconds, start the engine, idle for 10 minutes undisturbed.
How AutoDetective AI Can Help
AutoDetective's AI differentiates between the TLX's 2.0L turbo and 3.0L twin-turbo to rank causes specific to your engine. Upload your scan data for a free tailored diagnosis.