P0121 on Your All-New 2024 Toyota 4Runner
Your 6th-generation 2024 4Runner has flagged P0121 — throttle position sensor range/performance. This completely redesigned 4Runner debuts on the TNGA-F platform with the 2.4L turbocharged i-FORCE engine (T24A-FTS), replacing the venerable 4.0L V6. P0121 on this brand-new powertrain points primarily to software calibration and first-year production issues.
What You're Noticing
- Check engine light on
- Throttle response feels slightly off
- Idle may fluctuate mildly
- 8-speed automatic shift timing seems imprecise
- Possible boost hesitation under light load
Common Causes (Ranked by Likelihood)
1. ECU Software Calibration
The 2024 4Runner is a ground-up redesign with an all-new turbocharged engine. First-year calibration refinements for throttle body adaptation are expected. Toyota likely has updates available or in development.
2. Throttle Body Manufacturing Variance
New engine, new throttle body specifications. Occasional units with marginal sensor calibration are covered under warranty.
3. Connector/Wiring Issue
First-year production on a new platform can have minor assembly variations in connector seating or wiring routing.
4. Turbo Boost Calibration Interaction
The 2.4T's boost control system interacts with the throttle body differently than the old naturally aspirated V6. Calibration mismatches can produce TPS performance codes.
5. Early Carbon (Unlikely)
The 2.4T uses direct injection, making it more carbon-prone than the old V6. At low mileage, unlikely — but the 4Runner's off-road use with lots of idle time could theoretically accelerate deposits.
Diagnostic Steps
- Toyota dealer scans with Techstream
- Check for TSBs or recalls on the 2024 4Runner 2.4T
- Verify throttle body connector engagement
- Monitor TPS and boost data simultaneously
- Check for ECU software updates
Repair Costs
- All repairs under warranty: $0
- Software update (out of pocket): $100–$200
- Throttle body replacement (out of pocket): $350–$600
Can I Drive With P0121?
Yes for daily driving. Use caution on trails until resolved — precise throttle control is important for off-road obstacles. Schedule a dealer visit within a week or two.
DIY vs Professional
Your 2024 4Runner is under Toyota's 3-year/36,000-mile warranty. Take it to the dealer — free repair. Do not attempt DIY on a turbocharged vehicle under warranty.
Frequently Asked Questions
Is P0121 related to the new 2.4T engine?
Possibly. All-new powertrains commonly need software refinements in their first year. This is normal and covered under warranty.
Will the 2.4T need more throttle body maintenance than the old V6?
The direct-injection turbo is inherently more prone to carbon than the port-injected 4.0L V6. Long-term, throttle body cleaning will likely need to happen more frequently.
Does P0121 affect the 4Runner's off-road systems?
Multi-Terrain Select and Crawl Control use throttle input as part of their algorithms. Imprecise TPS data can make these systems less predictable. Fix before relying on them for serious trail work.
Is the 2024 4Runner reliable despite P0121?
Too early for long-term data, but the T24A-FTS engine has been used in the Lexus NX and Highlander with good results. P0121 on a first-year redesign is typically software-related, not a fundamental issue.