What Does P0121 Mean on a 2024 Nissan Sentra?
A P0121 code on your 2024 Nissan Sentra points our diagnostic investigators to the throttle position sensor (TPS). The sensor is transmitting voltage within normal boundaries but with an abnormal pattern—the ECM detects readings that conflict with its calculations from accelerator pedal input, airflow measurements, and engine load.
The 2024 Sentra runs Nissan's 2.0L MR20DD four-cylinder engine (149 hp) with a CVT. This engine uses a combination of direct and port injection (dual injection), which helps keep the intake and throttle body cleaner than direct-injection-only engines. The electronic throttle body houses the integrated TPS.
Common Symptoms to Watch For
- Check engine light on
- Hesitation when accelerating from stops
- Rough or unstable idle
- Sluggish response during passing maneuvers
- CVT may feel hesitant or jerky
- Reduced fuel economy
Top Causes Ranked by Likelihood
- ECM software calibration (35%) – On a current-year vehicle, a software update is the most likely resolution. Cost: $0 under warranty.
- Throttle body manufacturing defect (30%) – A factory defect in the throttle body or TPS element. Cost: $0 under warranty.
- Wiring or connector assembly defect (20%) – Manufacturing variability in harness crimps or pin seating. Cost: $0 under warranty.
- Carbon buildup (10%) – Unlikely at low mileage. The dual-injection system further reduces carbon risk. Cost: $120–$250 if not under warranty.
- Intake system leak (5%) – A loose factory clamp or gasket defect. Cost: $0 under warranty.
How Serious Is This Code?
P0121 is medium severity. Your Sentra should remain functional, but the 2.0L engine has limited power reserves—any throttle lag is very noticeable. Schedule a dealer visit soon.
Diagnostic Path
Take your 2024 Sentra to a Nissan dealer. They'll use CONSULT to monitor TPS data, check for calibration updates, and search Nissan's TSB database. On a new vehicle, dealer diagnostics are the most efficient approach.
Can You Fix This Yourself?
Your 2024 Sentra is fully covered under Nissan's 3yr/36k basic warranty and 5yr/60k powertrain warranty. Go to the dealer—there's no cost to you.
Get a Free AI Diagnosis
Get an informed perspective before your dealer appointment. AutoDetective's free AI diagnosis can assess your 2024 Sentra's symptoms and provide talking points for your service advisor.