What Does P0121 Mean on a 2022 Kia Carnival?
A P0121 on your 2022 Kia Carnival—Kia's versatile minivan—directs our diagnostic investigation to the throttle position sensor (TPS). The sensor is transmitting within the normal voltage range but with an abnormal performance pattern the ECM flags as inconsistent with other engine data.
The 2022 Carnival is powered by the 3.5L Lambda III V6 (290 hp) with an 8-speed automatic. This V6 uses multi-point injection (port injection), which keeps the throttle body naturally cleaner than direct-injection engines. The TPS is integrated into the electronic throttle body assembly.
Common Symptoms to Watch For
- Check engine light on
- Hesitation during acceleration, concerning with a loaded vehicle
- Rough or fluctuating idle
- 8-speed automatic may shift at unexpected points
- Reduced power during highway merging
- Smart Cruise Control may not respond smoothly
Top Causes Ranked by Likelihood
- Carbon buildup on throttle body (30%) – At 2-4 years, early deposits from PCV gases are possible despite port injection. Cost: $150–$300.
- Throttle body assembly failure (25%) – Internal TPS defect. Cost: $0 under warranty; $300–$520 otherwise.
- ECM software calibration (25%) – The Carnival was new for 2022—calibration updates are relevant. Cost: $0 under warranty.
- Wiring or connector issue (15%) – Assembly variability on a new model. 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 Carnival carries families—reliable acceleration matters for merging with passengers aboard. Fix this soon.
Diagnostic Path
Your 2022 Carnival is under Kia's warranty. Dealer KDS diagnostics, TSB checks, and repairs are all covered.
Can You Fix This Yourself?
Kia's 5yr/60k basic + 10yr/100k powertrain (original owner) covers everything. Go to the dealer—it's free.
Get a Free AI Diagnosis
AutoDetective's free AI diagnosis provides a targeted analysis of your Carnival's P0121 before your dealer appointment.