Tracking Down P0120 in Your 2022 Buick Enclave
When "Reduced Engine Power" appears on your 2022 Enclave's driver information center, followed by a sluggish response from the gas pedal, the detective work points to P0120 — a throttle position sensor circuit malfunction. Your second-generation Enclave rides on GM's C1XX platform with the 3.6L V6 (LGX engine), featuring GM's Throttle Actuator Control (TAC) system. This fully electronic throttle system has no cable — the pedal talks to the ECU, which commands the throttle body. When the TPS circuit sends bad data, the ECU shuts things down for safety.
Evidence at the Scene
- "Reduced Engine Power" message on the dash
- Check engine light illuminated
- Severe power loss — vehicle may barely accelerate
- Rough or fluctuating idle
- Throttle pedal feels unresponsive or sticky
- Engine may stall at stops
Prime Suspects
1. Electronic Throttle Body Failure
The GM ACDelco throttle body on the 3.6L V6 is a known failure point. The internal TPS and DC motor wear out, producing erratic voltage signals. This is the single most common cause of P0120 on the Enclave. The TPS is integrated — you replace the entire throttle body unit.
2. TAC Module Communication Error
The Throttle Actuator Control module manages communication between the pedal sensors, throttle body, and ECU. A software glitch or module failure can generate false P0120 codes. GM has issued TSBs for TAC-related issues on several platforms.
3. Throttle Body Connector Corrosion
Water intrusion or road salt can corrode the throttle body electrical connector. The Enclave's engine layout exposes this connector to splash zones. Even minor corrosion on the signal pins can produce P0120.
4. Wiring Harness Damage
The wiring between the throttle body and ECU runs through hot engine bay areas. Heat embrittlement or rodent damage to the harness insulation can cause shorts or opens in the TPS circuit.
5. Accelerator Pedal Position Sensor
The Enclave's pedal assembly contains dual APP sensors. If one fails or develops excessive resistance, the ECU may log P0120 rather than a pedal-specific code, especially if the signals conflict with throttle body feedback.
Investigation Steps
- Scan for codes using a GM-compatible scanner — check for companion TAC codes
- Inspect throttle body connector for corrosion — clean or replace if needed
- Monitor live TPS voltage data (should read 0.5V closed, sweep to 4.5V WOT)
- Check for GM TSBs related to throttle body or TAC on the C1XX platform
- Test APP sensor voltages at the pedal connector
Cost Breakdown
- Throttle body replacement (ACDelco OEM): $250–$500
- TAC module repair/reprogram: $200–$400
- Connector cleaning/repair: $100–$250
- Wiring harness repair: $150–$400
- APP sensor/pedal assembly: $150–$350
Can I Drive With P0120?
In Reduced Engine Power mode, the Enclave limits you to very low speeds — barely enough to limp off the road. Do not attempt highway driving. This is a safety-critical system. Have it towed to a GM dealer or qualified shop. Check your warranty status — a 2022 Enclave may still be within GM's 3-year/36,000-mile bumper-to-bumper coverage depending on purchase date and mileage.
DIY vs Professional
Throttle body replacement on the 3.6L V6 Enclave is a moderate DIY job — the throttle body is accessible and secured by four bolts. However, the new unit requires a relearn procedure using a scan tool capable of GM TAC relearn. If you have a quality OBD-II scanner with bi-directional control, this is doable at home. Otherwise, have a shop handle it for proper calibration.
Frequently Asked Questions
What does Reduced Engine Power mean on a Buick Enclave?
It means the ECU has detected a problem with the electronic throttle system and has limited engine output to prevent unsafe throttle behavior. P0120 is one of the most common triggers for this warning.
How much does a throttle body cost for a Buick Enclave?
An ACDelco OEM throttle body runs $150–$280 for the part. With professional installation and relearn procedure, expect $250–$500 total.
Is P0120 a common problem on the Buick Enclave?
Throttle body issues are a known concern across GM's 3.6L V6 platform, which includes the Enclave. The electronic throttle body is considered a wear item on higher-mileage GM vehicles.
Do I need a scan tool after replacing the throttle body?
Yes. After replacing the throttle body on a GM vehicle, a TAC (Throttle Actuator Control) relearn procedure must be performed using a scan tool with bi-directional capability. The engine will not idle correctly without this step.