What Does P0121 Mean on a 2022 Jeep Grand Cherokee?
A P0121 code on your 2022 Jeep Grand Cherokee indicates the PCM has detected an abnormal signal pattern from the throttle position sensor (TPS). The voltage is within range but doesn't track properly with your accelerator pedal input and engine load. Your Grand Cherokee's computer has identified a clue that the throttle system needs investigation.
The 2022 Grand Cherokee (WL—first year of the new generation) offers the 3.6L Pentastar V6, 5.7L Hemi V8, and the 4xe plug-in hybrid. The Pentastar uses a combination of port and direct injection, the Hemi uses port injection, and the 4xe's 2.0L turbo uses direct injection. All feature electronic throttle control with integrated TPS. At 2-4 years old, carbon buildup is possible but software and connector issues are equally likely.
Top Causes of P0121 on the 2022 Grand Cherokee
- Carbon buildup on throttle body – More likely on the DI turbo 4xe engine. Likelihood: 35%
- PCM software calibration – First-year WL platform; Jeep released updates. Likelihood: 25%
- Throttle body assembly issue – Internal TPS defect. Likelihood: 20%
- Connector or wiring issue – Corrosion, loose pins, or assembly defect. Likelihood: 15%
- Intake or boost leak – Particularly on the 4xe turbo model. Likelihood: 5%
Symptoms You May Notice
- Check Engine Light on
- Rough or unstable idle
- Hesitation during acceleration
- Reduced engine power
- Traction control or ESC warnings
- 4xe: transition between EV and gas modes may feel rough
How Serious Is This Code?
P0121 is medium severity. Your 2022 Grand Cherokee remains drivable but with potentially degraded throttle response. Address it soon—within 1-2 weeks. The code can affect the advanced driver-assist features that rely on consistent throttle control.
Diagnostic Steps
- Scan for codes and freeze frame data—note engine and conditions at code set
- Inspect throttle body for carbon deposits
- Monitor TPS voltage: ~0.5V idle, smooth sweep to ~4.5V WOT
- Check the throttle body connector for secure fit and clean pins
- Inspect wiring for damage or chafing
- Check for TSBs via wiTECH at the dealer
Estimated Repair Costs
- Under warranty: $0 (if still within 3-year/36,000-mile basic warranty)
- Throttle body cleaning: $100–$220
- Throttle body replacement: $400–$700
- PCM reflash: $100–$150 at dealer
Can You DIY This Fix?
DIY feasibility is moderate. If your warranty has expired, throttle body cleaning is a straightforward starting point. The Grand Cherokee's engine bay provides good access. Use dedicated throttle body cleaner. After cleaning, disconnect the battery for 15-20 minutes, reconnect, start, and idle 10 minutes for the relearn.
Check your warranty status—the 2022 Grand Cherokee may still be within the 3-year/36,000-mile basic warranty. The 5-year/60,000-mile powertrain warranty is certainly active. If covered, let the dealer fix it for free.