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HOMESERVICE MANUALSTOYOTA2004MATRIX XR, FWD, STANDARDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 770 (ENGINE CONTROL SYSTEM - DIAGNOSIS)CIRCUIT INSPECTIONDTC P2121: THROTTLE/PEDAL POSITION SENSOR/SWITCH "D" CIRCUIT RANGE/PERFORMANCEINSPECTION PROCEDUREOBD II SCAN TOOL (EXCLUDING HAND-HELD TESTER)
2004 Toyota Matrix XR, FWD, Standard

OBD II scan tool (excluding hand-held tester)

2004 Toyota Matrix XR, FWD, StandardSECTION OBD II scan tool (excluding hand-held tester)
WARNING: This page is about a different car, the 2004 Lexus IS 300. However, it is still accessible from the selected car via links, so may be relevant.
  1. Check voltage between terminals VPA and E2, and VPA2 and E2 of ECM connector. 

    PREPARATION: 

    1. Remove the ECM hood (See ENGINE CONTROL MODULE (ECM) ).
    2. Turn the ignition switch ON.

    CHECK: 

    Measure the voltage between terminals VPA and E2, and VPA2 and E2 of the ECM connector.

    Fig 1: Measuring Voltage Between Terminals VPA And E2, And VPA2 And E2 Of ECM Connector
    G01496502Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    OK: 

    Fig 2: Accelerator Pedal Voltage Chart
    G01496501Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. OK: Go to step   3 . 
    2. NG: Go to next step. 
  2. Check for open and short in harness and connector between accelerator pedal position sensor and ECM (See  HOW TO USE THE DIAGNOSTIC CHART AND INSPECTION PROCEDURE  ). 
    1. NG: Repair or replace harness or connector. 
    2. OK: Replace accelerator pedal position sensor (See  REPLACEMENT  ). 
  3. Is the DTC P2121 being output again? 

    PREPARATION: 

    1. Clear the DTC (See PRE-CHECK  ).
    2. Start the engine.
    3. Run the engine at idle for 15 seconds or more.

    CHECK: 

    1. Read the DTC (See PRE-CHECK  ).

    Result: 

    Fig 3: Display (DTC Output) Chart
    G01496503Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. B: System OK 
    2. A: Replace ECM (See  HOW TO USE THE DIAGNOSTIC CHART AND INSPECTION PROCEDURE  ). 
RENDER: 1.0x

NO RELATED

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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.