P0121 on the All-New 2024 GMC Canyon
A P0121 code on your 2024 GMC Canyon indicates the ECM has flagged an inconsistency in the throttle position sensor signal. The TPS readings are within normal voltage bounds, but the pattern is off—our detective's evidence points to something interfering with the smooth operation of the electronic throttle body.
The 2024 Canyon rides on GM's all-new midsize truck platform, powered exclusively by a 2.7L turbo-four direct-injection engine producing 310 hp. This high-output DI turbo engine demands precise throttle control for managing boost, and the electronic throttle body is at the center of that system. Being a DI-only engine (no port injection supplement), it's inherently more susceptible to carbon accumulation.
Symptoms You May Experience
- Check engine light on
- Reduced Engine Power message possible
- Turbo lag that seems worse than normal
- Rough or surging idle
- Hesitation on tip-in acceleration
Most Probable Causes
- Carbon buildup on throttle body – The 2.7L turbo's DI-only fuel system means all carbon from PCV and blow-by vapors collects on intake-side components including the throttle body. Likelihood: 35%
- ECM software calibration – The new Canyon platform is in its second model year, and GM frequently releases throttle and boost management updates for new engines. Likelihood: 30%
- Throttle body defect – Manufacturing quality issues are possible on a new platform. The integrated TPS or actuator motor may have a factory fault. Likelihood: 20%
- Wiring or connector issue – Loose pin connection or routing interference from factory assembly. Likelihood: 10%
- Turbo/boost system interaction – Wastegate or blow-off valve issues creating pressure anomalies at the throttle body. Likelihood: 5%
Repair Costs
- All repairs: $0 under warranty
- Out-of-warranty reference: Cleaning $80–$150, replacement $350–$600, software update $100–$200
Go Straight to the Dealer
Your 2024 Canyon is fully covered under GM's 3-year/36,000-mile bumper-to-bumper and 5-year/60,000-mile powertrain warranty. Do not attempt DIY repairs—take it to your GMC dealer. As a relatively new platform, the dealer can check for Technical Service Bulletins specific to the 2.7L turbo throttle system and apply any pending ECM recalibrations. All work will be performed at no cost to you.
How AutoDetective AI Can Help
Let AutoDetective's AI analyze your Canyon's freeze frame data and engine parameters. We'll give you a preliminary diagnosis specific to the 2.7L turbo platform so you know what to expect at the dealership.