What Does P0121 Mean on a 2024 Ram 3500?
A P0121 code on your 2024 Ram 3500 indicates the PCM has detected an abnormal TPS signal. On a brand-new heavy-duty truck, this should be resolved under warranty immediately—throttle reliability is critical for safe towing.
The 2024 Ram 3500 offers the 6.4L Hemi V8 or 6.7L Cummins High Output turbo-diesel. At low mileage, software calibration is the primary suspect.
Top Causes of P0121 on the 2024 Ram 3500
- PCM software calibration – New model year updates. Likelihood: 40%
- Factory throttle body defect – Manufacturing issue. Likelihood: 25%
- Connector assembly issue – Not properly seated. Likelihood: 20%
- HD vibration – Heavy-duty components and vibration. Likelihood: 10%
- Carbon buildup – Unlikely at low mileage. Likelihood: 5%
Symptoms You May Notice
- Check Engine Light on
- Inconsistent idle
- Hesitation during acceleration
- Reduced towing confidence
- Cruise control issues
How Serious Is This Code?
P0121 is medium severity. Your 2024 Ram 3500 remains drivable. For a truck with 37,000+ lb towing capacity, schedule a dealer visit immediately.
Diagnostic Steps
- Take to dealer—full warranty applies
- Dealer uses wiTECH for diagnostics
- Check for engine-specific software updates
- Inspect throttle body and connector
- Monitor live TPS data under load
Estimated Repair Costs
- Under warranty: $0 (full Stellantis warranty coverage)
- PCM reflash: $0 under warranty
- Throttle body replacement (if out of warranty): $400–$700
Should You DIY This?
DIY feasibility is low. Your 2024 Ram 3500 is under full warranty. Let the dealer handle it at no cost.