What Does P0121 Mean on a 2024 Jeep Wrangler?
A P0121 code on your 2024 Jeep Wrangler indicates the PCM has detected that the throttle position sensor (TPS) signal isn't following the expected voltage pattern. The signal is present but behaves erratically relative to your accelerator pedal input and engine operating conditions. On a new Wrangler, this is an uncommon finding that deserves immediate dealer investigation.
The 2024 Wrangler (JL) offers two engine options: the 3.6L Pentastar V6 and the 2.0L Hurricane turbo-four. Both use electronic throttle control with the TPS integrated into the throttle body. The Pentastar uses a combination of port and direct injection (starting in 2024), while the 2.0L turbo uses direct injection exclusively. On a nearly new vehicle, carbon buildup is unlikely—the investigation should focus on software and hardware causes.
Top Causes of P0121 on the 2024 Wrangler
- PCM software calibration – New model year may need a throttle control update. Likelihood: 35%
- Factory throttle body defect – Manufacturing issue with the integrated TPS. Likelihood: 25%
- Connector issue from assembly – Plug not fully seated or pinched wire from the factory. Likelihood: 20%
- Electrical interference – Signal noise on the TPS circuit from aftermarket accessories (lights, winch, etc.). Likelihood: 15%
- Carbon buildup – Unlikely at low mileage. Likelihood: 5%
Symptoms You May Notice
- Check Engine Light (MIL) on
- Rough or unstable idle
- Hesitation on acceleration
- Reduced engine power
- Electronic Stability Control (ESC) warnings
- Cruise control may not engage
How Serious Is This Code?
P0121 is medium severity. Your 2024 Wrangler remains drivable, but throttle response may be unpredictable—especially important if you're off-roading where precise throttle control matters. Address it soon—schedule a dealer appointment this week. Full warranty coverage applies.
Diagnostic Steps
- Take the Wrangler to your Jeep dealer—this is a warranty repair
- The dealer will use wiTECH to pull full diagnostic data
- Check for TSBs and software updates for the 2024 Wrangler
- Inspect throttle body connector and wiring quality
- If aftermarket accessories are installed, check for electrical interference
- Monitor live TPS data during test drive
Estimated Repair Costs
- Under warranty: $0 (covered by Stellantis 3-year/36,000-mile basic warranty)
- PCM software flash: $0 under warranty
- Throttle body replacement (if out of warranty): $350–$600
Should You DIY This?
DIY feasibility is low. Your 2024 Wrangler is fully covered under Stellantis' 3-year/36,000-mile basic warranty and 5-year/60,000-mile powertrain warranty. Let the dealer handle it at no cost. PCM software updates require Jeep's proprietary wiTECH diagnostic system. If you've added aftermarket accessories, mention them to the technician as they could be contributing to electrical interference on the TPS circuit.