P0120 Detected on Your 2024 Buick Encore GX
Seeing "Reduced Engine Power" on your 2024 Encore GX's display is the last thing you expected from a nearly new vehicle. P0120 flags a throttle position sensor circuit malfunction in the drive-by-wire throttle system. The 2024 Encore GX continues on the VSS-F platform with an updated 1.2L or 1.3L turbocharged three-cylinder, and the electronic throttle body remains a fully integrated unit. On a vehicle this new, the investigation typically points away from wear and toward manufacturing or software issues.
What You'll Experience
- "Reduced Engine Power" message displayed
- Check engine light illuminated
- Vehicle barely accelerates — limited to 15-25 mph
- Throttle input may feel disconnected
- Idle may surge or stumble
Leading Causes
1. Throttle Body Manufacturing Defect
At low mileage, a factory defect in the electronic throttle body — bad solder joint, defective potentiometer track, or contamination — is the most probable cause. This is a warranty claim.
2. ECU Software Update Needed
GM frequently releases software calibrations post-production. A throttle body adaptation or TAC calibration update may resolve P0120 without any hardware replacement.
3. Loose Connector from Assembly
If the throttle body electrical connector wasn't fully clicked into place during factory assembly, road vibration can cause intermittent contact loss and trigger P0120.
4. Wiring Routing Issue
A harness pinched against a bracket or heat shield during engine assembly can develop insulation failure, shorting the TPS signal wire to ground or power.
5. Pedal Position Sensor Defect
Rare on new vehicles, but a defective accelerator pedal sensor can send signals that conflict with throttle body feedback, causing the ECU to flag P0120.
Diagnostic Path
- Dealer scan with GDS2 for complete fault analysis
- Check for GM TSBs or software updates for the 2024 Encore GX
- Verify throttle body connector seating and pin condition
- Review freeze frame data for TPS voltage at time of fault
- Inspect harness routing for pinch points near turbo and exhaust
Repair Costs
- All repairs under warranty: $0
- Throttle body replacement (if out of pocket): $200–$450
- Software calibration: $0 under warranty
Can I Drive With P0120?
Not practically. Reduced Engine Power mode makes the Encore GX barely mobile. Use OnStar roadside assistance (standard on 2024 models) to arrange a tow to your Buick dealer.
DIY vs Professional
Take it to the Buick dealer. Your 2024 Encore GX is fully covered under GM's bumper-to-bumper warranty (3yr/36k) and powertrain warranty (5yr/60k). No reason to pay anything or risk voiding coverage with DIY attempts.
Frequently Asked Questions
Is P0120 a recall issue on the 2024 Encore GX?
As of now, there is no recall specifically for P0120 on the 2024 Encore GX. However, the dealer may find an applicable TSB (Technical Service Bulletin) with a software fix. Check with your dealer.
Will the dealer give me a loaner car?
Most Buick dealers provide courtesy transportation or a rental vehicle for warranty repairs that take more than a day. Ask when you schedule the service appointment.
How common is P0120 on new GM vehicles?
Electronic throttle faults on brand-new vehicles are uncommon but not unheard of. Manufacturing tolerances occasionally produce units that fail early. The warranty exists specifically for these situations.
Can clearing the code fix the problem?
No. Clearing P0120 without addressing the cause will result in the code returning, often within minutes of driving. The underlying fault must be repaired.