Following the P0120 Trail on Your 2022 Buick Envision
When your 2022 Envision displays "Reduced Engine Power" and the acceleration drops to a crawl, the evidence trail leads to P0120 — a throttle position sensor circuit malfunction. Your second-generation Envision sits on GM's E2XX platform with a 2.0L turbocharged four-cylinder (LSY engine), using a fully electronic throttle body where the TPS is integrated into the unit. The ECU has detected voltage signals from this circuit that don't match expected values, triggering the protective power reduction.
Symptoms Under the Magnifying Glass
- "Reduced Engine Power" message on the instrument panel
- Check engine light illuminated
- Significant power loss — vehicle struggles to maintain speed
- Throttle response feels numb or delayed
- Idle speed may wander or the engine may stall
- Occasional surging under light throttle
Key Suspects
1. Throttle Body Failure
The 2.0T LSY engine's electronic throttle body is the most common P0120 culprit on this platform. The internal TPS potentiometer develops dead spots or the drive motor weakens, producing out-of-range voltage signals. The TPS cannot be replaced independently — the entire throttle body unit is swapped.
2. Carbon Buildup on Throttle Bore
Direct injection produces significant crankcase vapor contamination. The 2.0T LSY engine routes these vapors through the intake, where they coat the throttle bore and plate. Heavy carbon deposits can impede smooth throttle operation and corrupt TPS readings.
3. Throttle Body Wiring Corrosion
The Envision's engine bay layout routes the throttle body harness near coolant lines and the turbo. Corrosion or heat damage to the connector or wiring can cause intermittent or persistent P0120 codes.
4. TAC Module Software Glitch
GM's Throttle Actuator Control system can develop calibration drift. A TAC relearn or software update through GDS2 may resolve P0120 without hardware replacement.
5. APP Sensor Degradation
The dual accelerator pedal position sensors can develop wear at commonly used throttle positions, creating signal conflicts that the ECU logs as a throttle position circuit fault.
Investigation Procedure
- Scan for DTCs — look for companion codes (P0121, P0122, P0220, P2135)
- Inspect throttle body and connector for carbon deposits and corrosion
- Monitor live TPS data at idle and during slow throttle sweep
- Check for GM TSBs on the E2XX platform throttle system
- Verify APP sensor signal correlation with TPS readings
Cost Breakdown
- Throttle body replacement (ACDelco): $250–$500
- Throttle body cleaning + relearn: $150–$300
- Wiring/connector repair: $100–$350
- TAC relearn/software update: $100–$200
- APP sensor/pedal assembly: $150–$350
Can I Drive With P0120?
In Reduced Engine Power mode, driving is barely possible and certainly not safe in traffic. Do not attempt highway driving. Have the Envision towed to a shop. Check your warranty status — a 2022 model may still be under GM's 3-year/36,000-mile bumper-to-bumper coverage.
DIY vs Professional
Check warranty coverage first. If expired, throttle body replacement on the 2.0T Envision is reasonably accessible — the throttle body sits atop the engine near the intake. You'll need an OBD-II scanner capable of GM TAC relearn after installation. Carbon cleaning is a solid first step before committing to full replacement — it's cheaper and often resolves the issue.
Frequently Asked Questions
What engine does the 2022 Buick Envision have?
The 2022 Envision comes exclusively with a 2.0L turbocharged four-cylinder (LSY engine code) producing 228 hp. It uses a fully electronic throttle body with an integrated TPS sensor.
Can carbon cleaning fix P0120?
If carbon buildup is the root cause, yes. A professional throttle body cleaning ($150–$300) followed by a TAC relearn procedure often resolves P0120 on the 2.0T engine. If the internal sensor or motor has failed, replacement is needed.
Is the 2022 Envision under warranty for throttle issues?
If purchased new, the 3-year/36,000-mile bumper-to-bumper warranty may still apply depending on mileage. The 5-year/60,000-mile powertrain warranty also covers engine-related components. Check your mileage and purchase date.
What does TAC relearn mean?
TAC (Throttle Actuator Control) relearn is a calibration procedure performed with a scan tool after throttle body cleaning or replacement. It allows the ECU to relearn the throttle body's resting position and operating range. Without it, the engine may idle roughly or stall.