1. What is P2108 in Chevrolet Silverado?

The P2108 OBD-II code stands for Throttle Actuator Control (TAC) System Forced Limited Power. For the Chevrolet Silverado 1500 (2016-2024)—a leader in full-size pickup sales—this code targets the electronic throttle control system in the 5.3L EcoTec3 V8 engine, standard in LT, LTZ, High Country, and Custom trims (paired with 6L80 6-speed or 10L80 10-speed automatic transmissions).

The TAC system replaces mechanical throttle cables with a computerized setup: the Accelerator Pedal Position (APP) sensor detects driver input, the electronic throttle body regulates airflow, and the PCM (Powertrain Control Module) synchronizes these components. P2108 triggers when the PCM detects a critical TAC system malfunction—forcing the Silverado into "limited power mode" (limp mode) to prevent engine damage.

Silverado Specific Note: This code is prevalent in 2018-2023 Silverado 1500 5.3L models, per Chevrolet Technical Service Bulletin (TSB) 22-NA-089. The 5.3L’s direct injection and AFM (Active Fuel Management) systems increase throttle body carbon buildup and APP sensor wear—especially in trucks used for towing or stop-and-go commuting. P2108 is often linked to Silverado P2108 throttle body control issues and APP sensor voltage irregularities.

2. Common Causes of P2108 in 2016-2024 Silverado

P2108 in Silverado 1500 5.3L EcoTec3 models stems from TAC system failures—below are real-world cases diagnosed with the ICARZONE UR1000:

• Carbon-Clogged Throttle Body (2020 Silverado LT 5.3L): An LT owner with 89,000 miles reported limp mode and "Reduced Power" dash warning. The UR1000’s Throttle Body Position Test showed a 17% deviation between requested and actual position (normal: <10%). Cleaning the throttle body with specialized cleaner (#CRC 05350) removed carbon deposits, resolving P2108 and restoring full acceleration.
• Faulty Accelerator Pedal Position (APP) Sensor (2019 Silverado LTZ 5.3L): An LTZ owner’s P2108 was intermittent, occurring during highway acceleration. The UR1000’s APP Sensor Voltage Test showed erratic readings (0.3V–4.8V fluctuations, normal: 0.5V–4.5V). Replacing the APP sensor (OEM #12677836) fixed the signal issue—common in 2019-2022 Silverado P2108 cases.
• Damaged TAC System Wiring Harness (2021 Silverado High Country 5.3L): A High Country owner’s P2108 appeared after off-roading. The UR1000’s Circuit Continuity Test detected a short circuit in the throttle body connector—caused by debris impact. Repairing the wiring with heat-resistant connectors restored proper signal flow.
• PCM Software Glitch (2022 Silverado Custom 5.3L): A Custom owner’s P2103 cleared temporarily after restarting. The UR1000’s PCM Relearn Tool identified outdated TAC system calibration. Updating the PCM software via UR1000’s Chevy-specific firmware tool permanently resolved the code—critical for 2021-2024 Silverado P2108 troubleshooting.

3. Key Symptoms of P2108 in Silverado 5.3L EcoTec3

P2108 symptoms in the Silverado focus on TAC system-related performance issues—watch for these critical signs that affect driving safety and capability:

4. Silverado Trims/Engines Prone to P2108

Chevrolet service data highlights these 2016-2024 Silverado 1500 configurations with the highest P2108 occurrence rates (all 5.3L EcoTec3 V8):

5. Diagnose P2108 with ICARZONE UR1000

Diagnose P2108 in your Silverado 1500 5.3L EcoTec3 accurately with the UR1000’s Chevy-specific TAC system tools. Follow these steps (engine off, key in "ON" position):

Case Example: A 2019 Silverado LT failed Step 2 (16% deviation) and Step 5 (TSB 22-NA-089 eligible). The UR1000’s Component Location Tool guided throttle body access. Cleaning the throttle body and performing a TAC system relearn via UR1000 fixed P2108—verified by test drive (smooth acceleration, no limp mode with a 7,000-lb trailer).

6. How to Fix P2108 in Silverado 5.3L EcoTec3

Resolve P2108 in your Silverado with these UR1000-verified solutions—tailored to the 5.3L EcoTec3’s TAC system:

1. Clean Carbon-Clogged Throttle Body (Most Common Fix for TSB 22-NA-089)

1. Confirm clog via UR1000’s Step 2 (>10% deviation). Disconnect the negative battery terminal and air intake hose from the throttle body.
2. Locate the throttle body: Mounted on the intake manifold (driver’s side for 5.3L EcoTec3 engines).
3. Use the UR1000’s Throttle Body Relearn function to open the throttle blades (avoids damaging the actuator during cleaning).
4. Spray throttle body cleaner (#CRC 05350) onto the blades and housing—use a soft brush to remove carbon deposits (avoid metal tools).
5. Wipe clean with a lint-free cloth and let dry completely (10–15 minutes).
6. Reattach the air intake hose and battery terminal. Use UR1000 to perform a TAC system relearn (critical for PCM calibration).
7. Clear P2108 and test drive—verify smooth acceleration and no "Reduced Power" warning. This fix works for most 2018-2023 Silverado P2108 cases.

2. Replace Faulty APP Sensor

1. Confirm sensor failure via UR1000’s Step 3. Locate the APP sensor: Integrated into the accelerator pedal assembly (under the dash).
2. Disconnect the electrical connector (press the tab) and remove the pedal assembly mounting bolts (2 Torx screws).
3. Separate the APP sensor from the pedal assembly (1 Phillips screw) or replace the entire assembly (OEM options below):
   • 2016-2020 Silverado: #12677836 (sensor only)
   • 2021-2024 Silverado: #12680730 (updated pedal assembly with sensor)
4. Install the new sensor/assembly and torque bolts to 8 ft-lbs. Reconnect the electrical connector.
5. Use UR1000 to perform an APP sensor relearn. Clear P2108 and test drive—verify stable voltage readings (Step 3).

3. Repair TAC System Wiring Harness

1. Confirm wiring issues via UR1000’s Step 4. Locate the damaged section (common areas: throttle body connector, under-dash APP sensor wiring).
2. Cut out the damaged wiring (1–2 inches on each side of the break) and strip 1/4-inch of insulation from the ends.
3. Splice in heat-resistant wiring (rated for 250°F+) using crimp connectors. Cover splices with heat-shrink tubing.
4. Secure the repaired harness with zip ties to avoid contact with hot surfaces (exhaust manifold, engine block).
5. Retest continuity with UR1000 (Step 4) to confirm resistance <0.5Ω. Clear P2108 and test drive.

4. Update PCM Software

1. Confirm software glitch via UR1000’s Step 1 (no hardware issues detected). Connect the UR1000 to a Wi-Fi network.
2. Select "PCM" > "Chevrolet Calibration Update" > Enter Silverado VIN to retrieve the latest TAC system firmware.
3. Follow UR1000 prompts to install the update (do not turn off the tool or vehicle during installation—15–20 minutes).
4. After update, perform a TAC system relearn with UR1000. Clear P2108 and verify no recurrence during test drive—essential for 2021-2024 Silverado P2108 troubleshooting.

7. P2108 Repair Costs & Maintenance Tips

P2108 repair costs for the Silverado 5.3L EcoTec3 vary by cause. Use this table to budget:

Maintenance Tips for Silverado 5.3L EcoTec3 Owners

• LT/LTZ (towing users): Clean the throttle body every 60,000 miles (follows TSB 22-NA-089 guidelines) to prevent carbon buildup—key for P2108 Silverado limp mode prevention.
• Inspect TAC system wiring during oil changes—check for fraying near the throttle body and accelerator pedal assembly.
• Use UR1000’s TAC System Health Check every 15,000 miles—monitor throttle position and APP sensor voltage to catch issues early.
• Replace the APP sensor every 100,000 miles (preventive) — OEM sensors maintain consistent voltage signals, avoiding false P2108 codes.
• Use high-quality fuel (91+ octane for optimal performance) to reduce carbon formation in the throttle body.
• Avoid aggressive off-roading through debris-rich areas—protect the throttle body connector with a weatherproof cover (Chevy OEM #12646638).

8. Silverado-Specific FAQs