What Does P0121 Mean on a 2023 Ford Bronco Sport?
Our diagnostic detectives have opened a P0121 case on your 2023 Ford Bronco Sport—and the clues point to the throttle position sensor (TPS) delivering voltage signals within the expected range but following an abnormal pattern. The PCM sees the TPS communicating, but the readings don't match what it calculates based on engine load, airflow, and driver input.
The 2023 Bronco Sport uses Ford's C2 platform with either the 1.5L EcoBoost three-cylinder (181 hp) or the 2.0L EcoBoost four-cylinder (250 hp) in the Badlands trim. Both powertrains feature fully electronic throttle control with the TPS integrated into the throttle body—there's no separate sensor to replace.
Common Symptoms to Watch For
- Check engine light or wrench light illuminated
- Hesitation or flat spot during acceleration
- Unstable or hunting idle
- Momentary power dips during steady-speed driving
- Throttle response feels delayed or inconsistent
- Trail Control or G.O.A.T. modes may not respond as expected
Top Causes Ranked by Likelihood
- Carbon buildup on throttle body (35%) – Even on a newer vehicle, direct injection allows carbon to accumulate faster than port-injected engines. The throttle plate and bore can develop deposits that restrict smooth operation and distort TPS readings. Cost: $150–$300 for cleaning.
- Throttle body assembly defect (25%) – An internal manufacturing defect in the TPS resistive element can cause premature signal irregularities. Cost: $350–$550 for warranty replacement or out-of-pocket.
- PCM software calibration (20%) – Newer model years occasionally need software refinements. Ford may have issued updated calibrations for throttle body operation. Cost: $0 under warranty; $100–$180 otherwise.
- Wiring or connector issue (15%) – Vibration from off-road use or manufacturing defects in the harness connector can create intermittent signal problems. Cost: $100–$250 for repair.
- Intake boot or boost leak (5%) – A loose clamp or minor crack in the pressurized intake tract can cause airflow readings to conflict with throttle position data. Cost: $50–$200.
How Serious Is This Code?
P0121 rates as medium severity. Your 2023 Bronco Sport should remain drivable, but throttle response may be unpredictable—not ideal for a vehicle designed for adventurous driving. Address this soon, within a week, particularly before any planned trail outings.
Diagnostic Path
Connect FORScan and pull live TPS data. Perform a slow throttle sweep from closed to wide-open, watching for voltage dropouts or erratic jumps. Compare TPS voltage against accelerator pedal position sensor (APPS) data—they should track proportionally. Check for related codes like P0122 or P0123 that would narrow the investigation.
Inspect the throttle body bore for carbon deposits. Even at low mileage, the EcoBoost direct-injection design can produce noticeable buildup. Examine the wiring harness routing for any chafe points against the engine or chassis. Verify the latest PCM software version is installed.
Can You Fix This Yourself?
Your 2023 Bronco Sport should still be under Ford's 3yr/36k bumper-to-bumper warranty—take it to the dealer first. The diagnosis, any software updates, and throttle body replacement would all be covered at no cost. DIY troubleshooting before the dealer visit is fine, but don't void warranty coverage by performing unauthorized repairs.
Get a Free AI Diagnosis
Want to know exactly what's going on before your dealer appointment? Let AutoDetective's AI detective analyze your 2023 Bronco Sport's symptoms for a free, personalized diagnosis with cost estimates and repair recommendations.