P0121 on the Final 2023 Dodge Challenger
A P0121 code on your 2023 Dodge Challenger means the PCM has detected an inconsistency in the throttle position sensor signal. The readings are within voltage specs but the behavior doesn't match what the computer expects—our detective has found a discrepancy that needs investigating. Since 2023 marks the final year of this legendary muscle car, keeping it running right matters more than ever.
The 2023 Challenger carries the same proven powertrain lineup: 3.6L Pentastar V6, 5.7L Hemi V8, 6.4L SRT Hemi, and supercharged Hellcat variants. All use port fuel injection and electronic throttle control with integrated dual TPS signals.
Warning Signs
- Check engine light on
- Throttle response feels inconsistent
- Idle may hunt or surge slightly
- Brief hesitation during acceleration
- MDS behavior may feel rough on Hemi models
The Investigation: Probable Causes
- Carbon deposits on throttle body – Even on a low-mileage vehicle, PCV vapors and short-trip driving can produce deposits that restrict smooth throttle plate movement. Likelihood: 40%
- Throttle body component failure – Internal TPS or actuator motor fault in the electronic throttle body. Likelihood: 25%
- PCM software calibration – Stellantis released final software updates for the LX platform. An outdated calibration may trigger false P0121. Likelihood: 20%
- Wiring or connector issue – Corroded terminal or loose connector at the throttle body. Likelihood: 10%
- Intake tract leak – Loose air intake or throttle body gasket. Likelihood: 5%
Repair Costs
- Throttle body cleaning: $80–$150 (shop)
- Throttle body replacement: $250–$550 parts and labor
- PCM reflash: $100–$180 (dealer)
- Wiring repair: $100–$250
Take Advantage of Your Warranty
Your 2023 Challenger is fully covered under Stellantis's 3-year/36,000-mile basic warranty and 5-year/60,000-mile powertrain warranty. Take it to a Dodge dealer for a no-cost repair. The dealer will use wiTECH to diagnose the throttle system, perform a relearn, and check for final-year software updates. As the last ICE Challenger, dealer service records add significant collector value.
How AutoDetective AI Can Help
Let AutoDetective's AI analyze your 2023 Challenger's scan data before your dealer visit. We'll identify the most likely cause based on your engine variant and driving patterns so you can have an informed conversation with the service advisor.