P0120 Detected on Your 2024 Cadillac XT6
A P0120 code on your 2024 XT6 means the ECU has uncovered a throttle position sensor circuit malfunction. Your XT6's 3.6L V6 (LGX) relies on an electronic throttle body with an integrated TPS to regulate airflow — when this circuit sends abnormal signals, the system engages Reduced Engine Power mode. On a vehicle this new, manufacturing or software issues are the primary suspects rather than component wear.
Symptoms
- "Reduced Engine Power" message displayed
- Check engine light on
- Engine barely responds to throttle input
- Vehicle limited to very low speeds
- Possible idle instability
Probable Causes
1. Throttle Body Defect
A factory defect in the ACDelco electronic throttle body — bad potentiometer, contamination, or motor winding issue — is the leading cause on new vehicles.
2. PCM Software Update
A calibration update for the powertrain control module may address throttle body adaptation parameters released after your XT6's build date.
3. Connector Engagement Issue
If the throttle body connector wasn't fully clicked during factory assembly, road vibration causes intermittent signal dropout.
4. TAC Calibration
The Throttle Actuator Control system may require a recalibration through the GDS2 dealer tool.
5. Engine Ground Connection
A poor engine ground can cause voltage fluctuations across sensor circuits, including the TPS.
Diagnostic Steps
- Cadillac dealer GDS2 scan for complete diagnostic
- Search for TSBs and recalls on 2024 XT6 throttle
- Inspect connector seating
- Check for pending software updates
- Verify engine ground connections
Repair Costs
- All repairs under warranty: $0
- Throttle body replacement (out of pocket): $300–$650
Can I Drive With P0120?
Only at very low speed to exit traffic. Use Cadillac roadside assistance for a tow to the dealer. Do not attempt highway driving in Reduced Engine Power mode.
DIY vs Professional
Take it to the Cadillac dealer. Your 2024 XT6 is covered under the 4-year/50,000-mile bumper-to-bumper warranty and 6-year/70,000-mile powertrain warranty. No out-of-pocket cost for throttle system repairs.
Frequently Asked Questions
Is my 2024 XT6 repair covered?
Yes. Cadillac's full factory warranty covers throttle body and related electrical components at no cost to you.
How common is P0120 on new Cadillacs?
Electronic throttle faults on new vehicles are uncommon but occur occasionally due to manufacturing variability. The warranty exists to cover these situations.
Will the dealer provide a loaner?
Most Cadillac dealers offer complimentary loaner vehicles for warranty repairs. Arrange one when scheduling your appointment.
Can P0120 cause other problems?
The Reduced Engine Power mode prevents additional damage. However, repeated limp mode events can stress the transmission and other drivetrain components, so prompt repair is recommended.