2012 Lexus LS 460 AWDFACTORY OEM SERVICE PROCEDURE

DTC P2121: Throttle / Pedal Position Sensor / Switch "D" Circuit Range / Performance: Procedure

  1. READ VALUE USING TECHSTREAM (ACCELERATOR POSITION SENSOR) See step   1 

    OK → See step   3 

    NG: Go to next step 

  2. CHECK HARNESS AND CONNECTOR (ACCELERATOR PEDAL POSITION SENSOR - ECM) See step   2 

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  3. REPLACE ACCELERATOR PEDAL ROD ASSEMBLY 
    1. Replace the accelerator pedal rod assembly. Refer to REMOVAL .

    NEXT: Go to next step 

  4. CHECK WHETHER DTC OUTPUT RECURS (ACCELERATOR PEDAL POSITION SENSOR DTCS) 
    1. Connect the Techstream to the DLC3.
    2. Turn the engine switch on (IG) and turn the Techstream on.
    3. Clear DTCs. Refer to DTC CHECK / CLEAR .
    4. Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.
    5. Enter the following menus: Powertrain / Engine / Trouble Codes.
    6. Read DTCs.

      Result

      Display (DTC Output) Proceed to
      P2121 A
      No output B

    B → SYSTEM OK 

    A → See step   5 

  5. REPLACE ECM. Refer to  REMOVAL 
Factory Service Tools

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

Disclosure: Verified tool recommendations may earn an affiliate commission at no cost to you.

Shop Manual-Ready ToolsCompare Repair QuoteQuote Shield Pro

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.

Rather have a pro handle this?

A certified mobile mechanic comes to your home or office. They bring the tools, you stay comfortable. No tow truck, no waiting room, no surprises.

Comes to youSame-day available12-month warranty
Get a Free Quote

No obligation. See pricing before you book.