P2111 on 2016-2020 Lexus GS: Throttle Actuator Stuck Open Causes and Fixes

What's Unique About the 2016-2020 Lexus GS

For this generation of Lexus GS, the cause of P2111 can be engine-specific. On the high-performance GS F model with the 5.0L V8 (2UR-GSE) engine, Lexus issued a Technical Service Bulletin (TSB L-SB-0032-25) acknowledging a design issue that is resolved by replacing the throttle body with an updated part. For the more common V6 (2GR-FKS) and four-cylinder (8AR-FTS) models, the issue is more typical, usually stemming from carbon buildup that can be cleaned before resorting to a full replacement. Owner experiences confirm that cleaning is a viable first step, but if the code returns, replacement is the definitive fix.

Diagnostic Flowchart

Tap your situation to follow the diagnostic path that matches what you're seeing on this vehicle.

Symptoms You May Notice

• Vehicle enters a low-power "limp mode"
• Check Engine Light is on
• VSC, ABS, and/or other warning lights may illuminate on the dash
• Engine idle is high, surging, or erratic
• Vehicle feels like it's maintaining speed or accelerating slightly even after letting off the gas pedal
• Engine may run poorly and produce excessive white, stinky smoke from the exhaust if coolant is ingested through the stuck-open throttle (on models with coolant lines to the throttle body)

Most Likely Causes

1. Dirty or Binding Throttle Body 🔴 High Probability → Shop Fuel Injection Throttle Body Direct injection engines can be prone to carbon buildup in the intake tract, which can physically obstruct the throttle plate and prevent it from closing smoothly. The back side of the throttle plate is often the dirtiest area.
   How to confirm: Remove the intake air duct from the throttle body and visually inspect the throttle plate and bore for black, sooty carbon deposits. Check if the plate moves smoothly by hand (with the ignition off).
   Typical fix: Thoroughly clean the throttle body bore and plate with a dedicated throttle body cleaner and a soft, lint-free cloth. Do not spray cleaner directly into the electronics. 🎬 Watch: Step-by-step throttle body cleaning for the 2GR-FKS V6 engine. Disconnecting the battery before cleaning is recommended.
   Est. part cost: $10-$20
2. Failed Throttle Body Assembly 🔴 High Probability → Shop Fuel Injection Throttle Body For the 5.0L V8 (2UR-GSE) engine, Lexus issued TSB L-SB-0032-25 for this specific code, indicating an inherent issue with the original part. For all engines, the internal electronic motor, plastic gears, or position sensor can fail over time, a failure that cleaning will not fix.
   How to confirm: If the code returns quickly after a thorough cleaning, and the wiring is confirmed to be intact, the assembly itself is faulty. A mechanic can use a scan tool like Toyota's Techstream to command the throttle actuator and observe its response in real-time to confirm the failure.
   Typical fix: Replace the entire throttle body assembly with a new OEM part. For the GS F, ensure the replacement is the updated part number specified in the TSB. Aftermarket units are available but may have quality issues.
   Est. part cost: $450-$1000

Rare But Worth Checking

• Wiring or Connector Issue: The wiring harness leading to the throttle body can become damaged or the connector pins can corrode, causing an intermittent signal. This should be checked before replacing an expensive throttle body.
• Powertrain Control Module (PCM) Fault: → Shop Engine Control Module (ECM) In very rare cases, the fault can be with the PCM itself. This should only be considered after all other possibilities have been exhaustively ruled out by a professional.
• Foreign Object Obstruction: In rare instances, debris from the intake system can get lodged in the throttle body, physically jamming the plate. One owner on ClubLexus reported finding a piece of plastic that, once removed, solved the P2111 code.

Diagnosis Steps

1. Scan the vehicle's computer for P2111 and any other stored codes. Note the presence of P0505, especially on a GS F.
2. Disconnect the negative battery terminal to prevent electrical issues.
3. Remove the plastic engine covers and the intake air duct connected to the throttle body.
4. Visually inspect the throttle plate and the inside of the throttle body for heavy carbon buildup or foreign objects.
5. If carbon is present, clean it thoroughly using throttle body cleaner and a lint-free rag. Manually move the plate to clean all surfaces. Let it dry completely.
6. Inspect the wiring harness and connector at the throttle body for any signs of damage, corrosion, or loose pins.
7. Reassemble the intake, reconnect the battery, and start the engine.
8. Perform an idle relearn procedure. This may involve letting the engine warm up and idle for several minutes, or simply driving the vehicle for 10-15 miles until the idle speed normalizes. A common procedure is to warm the engine, turn it off, cycle the ignition 'On' then 'Off' twice, restart, engage the parking brake, put the car in Drive, and let it idle for 4-5 minutes.
🎬 Watch: How to perform a manual throttle idle relearn.
9. If the code returns, the throttle body assembly is the most likely culprit and should be replaced.
10. After replacement, clear all codes and perform a test drive to confirm the fix.

Parts You'll Likely Need

• Throttle Body Assembly (OEM #22030-38021 (Updated part for 2UR-GSE, supersedes 22030-38020). Part numbers for other engines will vary.) — This is the definitive fix if cleaning does not resolve the code. For the GS F (2UR-GSE engine), a modified version is required per TSB L-SB-0032-25.
  Trusted brands: Lexus (OEM), Aisin
  OEM price range: $900-$1200
  Aftermarket price range: $250-$500

Related Codes That Often Appear With This One

• P0505 — This code for 'Idle Control System' is specifically mentioned alongside P2111 in the Lexus TSB for the 2UR-GSE engine, as a stuck-open throttle directly affects the engine's ability to control its idle speed.

Technical Service Bulletins (TSBs) & Recalls

• L-SB-0032-25: Addresses a MIL ON condition with DTC P2111 and/or P0505 on vehicles with 2UR-GSE engines, recommending replacement with a modified throttle body assembly and ventilation hoses. This TSB also applies to other Lexus models with the same engine.

Platform-Specific Known Issues

• A known issue documented in Lexus Technical Service Bulletin (TSB) #L-SB-0032-25 affects models with the 5.0L 2UR-GSE V8 engine (GS F). It notes that a MIL ON condition with DTC P2111 and/or P0505 may occur, and the fix is to replace the throttle body assembly with a modified part and also replace ventilation hoses No. 2 and No. 3.

Mechanic-Grade Diagnostic Values

• ETCS Power Supply Voltage (+BM) — expected: Above 4V. Failure: If voltage drops below 4V, the ECU may cut current to the throttle control motor and log a fault like P2118.
• Throttle Actuator Motor Current — expected: Typically between 0.5A and 10A during operation.. Failure: A current draw of less than 0.5A or more than 10A can trigger related motor circuit faults like P2102 or P2103, indicating an open, short, or seized motor.
• Throttle Control Motor Resistance — expected: A specific Ohm value from the manufacturer (not found in searches).. Failure: An intermittent failure was diagnosed when a motor measured 169-172 ohms, which was stated to be far from the manufacturer's specification.

Hidden / Shadow Codes Worth Checking

• Freeze Frame Data: This is not a separate code, but a snapshot of all critical engine parameters (RPM, vehicle speed, coolant temp, etc.) at the exact moment the P2111 DTC was triggered. It is invaluable for diagnosing intermittent faults. (see via Accessible using a professional scan tool like Toyota Techstream via the 'Powertrain / Engine / Trouble Codes' menu.)
• All Readiness (DTC Judgment Result): After a repair, this utility checks the status of the self-diagnostics for a specific DTC. The result will show as NORMAL, ABNORMAL, or INCOMPLETE, confirming if the fault is truly gone or if the system hasn't completed its self-check yet. (see via Accessible in Toyota Techstream under 'Powertrain / Engine / Utility / All Readiness'.)

Scan Tool Commands That Help

• Toyota Techstream: Active Test: Control the Throttle Actuator — This bidirectional command allows a technician to manually command the throttle plate to open and close without using the accelerator pedal. It is the definitive way to confirm if the throttle plate is physically sticking or if the internal motor is failing to respond to commands.
• Toyota Techstream: Utility: All Readiness — After cleaning or replacing the throttle body, this function is used to confirm that the P2111 diagnostic monitor has run and passed, verifying the repair was successful.

Wiring & Ground Locations

• Throttle Body Connector — The 6-pin electrical connector on the throttle body assembly.. This connector provides power and signal to the throttle motor and position sensor. A broken clip, corroded pins, or damaged wires can cause intermittent loss of connection, leading to P2111. The pigtail part number is often 90980-11858 for Toyota/Lexus vehicles.
• Engine Harness Chafe Points — General areas to inspect include where the harness crosses the top of the camshaft/valve covers, near metal brackets (like the generator bracket), and around suspension components like the shock tower or upper control arm bushings.. Engine vibration can cause the wiring harness to rub against sharp metal edges, eventually wearing through the insulation and causing a short circuit in the throttle control wiring. This can mimic a component failure.
• Main Chassis Ground — A primary ground strap typically runs from the negative battery terminal to the inner fender/chassis. Additional grounds connect the chassis/firewall to the engine block, often at the rear of the cylinder heads.. A poor or corroded main ground connection can cause a variety of electrical issues, including erratic behavior from the Electronic Throttle Control System (ETCS), as it relies on a stable voltage and clean ground reference.

Real Owner Repair Stories

• YouTube user 'Saandlan' (2001-2005 Lexus IS300 (similar ETCS principle)) — Vehicle went into limp mode, throttle was unresponsive.
  ❌ Tried (didn't work) Replaced the throttle position sensor (TPS), Replaced the accelerator pedal position sensor (APPS), Replaced the throttle motor
  ✅ What actually fixed it The plastic electrical connector on the throttle body harness was old, brittle, and had a broken clip, preventing a secure connection. Replacing the connector shell itself resolved the limp mode and fault code.

OEM Part Supersession History

• 22030-38020 → 22030-38021 — This is the updated, modified throttle body assembly for the 5.0L 2UR-GSE engine as specified in TSB L-SB-0032-25 to resolve the P2111/P0505 condition.
  Heads up: Using the original part number (22030-38020) for a replacement on a 2UR-GSE engine may result in the P2111 code returning.