Tracking Down P0121 on Your 2022 GMC Canyon
When your 2022 GMC Canyon's ECM sets a P0121 code, it has detected irregular behavior from the throttle position sensor. The TPS voltage is within the acceptable range, but the signal doesn't follow the expected pattern based on your accelerator pedal input. It's like a detective discovering that a key witness's alibi doesn't hold up under scrutiny—something about the throttle response isn't adding up.
The 2022 Canyon is the last year of the previous generation, available with a 2.5L four-cylinder, 3.6L V6, or 2.8L Duramax diesel. All use electronic throttle control with an integrated TPS in the throttle body. The gas engines use port injection, which generally produces less carbon buildup than direct injection, but the throttle body can still accumulate deposits after years of service.
Symptoms to Look For
- Check engine light illuminated
- Reduced Engine Power mode activated
- Hesitation when pressing the accelerator
- Rough or unstable idle
- Difficulty maintaining steady speed on inclines
Ranked Causes
- Carbon buildup on throttle body – Even with port injection, years of PCV system vapors and intake tract deposits accumulate on the throttle plate. Likelihood: 45%
- Throttle body assembly wear – The internal motor and TPS sensors on the previous-gen Canyon's throttle body can develop wear at this age. Likelihood: 25%
- Wiring or connector fault – Trucks see more vibration and dust exposure than cars, which can affect connectors and wiring integrity. Likelihood: 15%
- Vacuum or intake leak – Cracked intake manifold gasket or deteriorated PCV valve/hose. Likelihood: 10%
- ECM software issue – Outdated throttle adaptation parameters. Likelihood: 5%
Estimated Repair Costs
- Throttle body cleaning: $80–$150 (shop) / $10–$20 (DIY)
- Throttle body replacement: $280–$500 parts and labor
- Wiring/connector repair: $100–$250
- PCV valve/hose replacement: $50–$150
DIY Feasibility: Moderate to High
The 2022 Canyon may still be under GM's 3-year/36,000-mile bumper-to-bumper warranty depending on mileage. Check your coverage first. If out of warranty, throttle body cleaning is very accessible on the Canyon—especially the 3.6L V6, where the throttle body sits right on top of the engine. After cleaning, perform the GM relearn procedure: disconnect the battery for 30 minutes, reconnect, start the engine, and idle for 15 minutes without pressing the gas.
How AutoDetective AI Can Help
Upload your OBD-II scan data to AutoDetective for an AI-powered diagnosis specific to your 2022 Canyon's engine and mileage. Our system identifies the most likely cause and estimates repair costs near you.