What Does P0121 Mean on a 2021 Kia Telluride?
Our diagnostic investigation into P0121 on your 2021 Kia Telluride reveals the throttle position sensor (TPS) is transmitting voltage within the expected range but with an abnormal performance pattern. The ECM sees data that doesn't match its calculations from pedal position, airflow, and engine load.
The 2021 Telluride—Kia's award-winning three-row SUV—is powered by the 3.8L Lambda II V6 (291 hp) with an 8-speed automatic. This V6 uses multi-point injection (port injection), which keeps the throttle body and intake valves naturally cleaner than direct-injection engines. The TPS is integrated into the electronic throttle body.
Common Symptoms to Watch For
- Check engine light on
- Hesitation during acceleration, especially loaded with passengers
- Rough or fluctuating idle
- 8-speed automatic may shift at unexpected points
- AWD torque distribution may feel off
- Smart Cruise Control may disengage
Top Causes Ranked by Likelihood
- Carbon buildup on throttle body (30%) – Even with port injection, PCV gases deposit carbon over time. At 3-5 years, early buildup is possible. Cost: $150–$300.
- Throttle body assembly failure (25%) – Internal TPS defect or early wear. Cost: $0 under warranty; $300–$530 otherwise.
- ECM software calibration (25%) – An available update that refines throttle monitoring. Cost: $0 under warranty.
- Wiring or connector issue (15%) – Corrosion or assembly variability. Cost: $0 under warranty; $80–$250 otherwise.
- Intake system leak (5%) – Gasket or vacuum issue. Cost: $0 under warranty.
How Serious Is This Code?
P0121 is medium severity. The Telluride is a family vehicle that carries up to 8 passengers—reliable throttle response matters for safe transport. Address this soon.
Diagnostic Path
Your 2021 Telluride is under Kia's warranty. Take it to the dealer for KDS diagnostics at no cost.
Can You Fix This Yourself?
Kia's 5yr/60k basic warranty covers your 2021 Telluride. Original owners have the 10yr/100k powertrain warranty. Dealer repair is free—use it.
Get a Free AI Diagnosis
Get a clear picture before your dealer visit. AutoDetective's free AI diagnosis provides targeted analysis of your Telluride's P0121.