Diagnosis & Repair

NOTE: Using hand-held tester or scan tool, read FREEZE FRAME data. Freeze frame data records engine conditions when malfunction is detected.

After confirming DTC P0120 use Toyota hand-held tester or scan tool to confirm throttle valve opening percentage with throttle fully closed and fully open to determine probable cause. If percentage displayed is always zero percent, VC circuit may be open or VTA circuit may be open or shorted. If percentage displayed is always approximately 100 percent, E2 circuit may be open.

For circuit wiring diagram, diagnosis and repair procedure, see Fig 1-Fig 3 .

For access to, or replacement of ECM, Engine Control Module (ECM) is located behind glove box. See Figure. For ECM connector view, see Figure. For testing of systems or components, see SYSTEM & COMPONENT TESTING - V6 & V8 article. For removal and installation of components, see REMOVAL & INSTALLATION - V6 & V8 article.

Fig 1: DTC P0120 Diagnostic Procedure (Steps 1-2)

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Fig 2: DTC P0120 Diagnostic Procedure (Steps 3-4)

Fig 3: DTC P0120 Diagnostic Procedure (Step 5)