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Home >> Toyota >> 2004 >> Matrix Base, FWD, Automatic >> Repair and Diagnosis >> External Pages >> Different car >> Section 106 (Engine Controls - Self-Diagnostics) >> Diagnostic Tests >> DTC P2120, DTC P2122, DTC P2123, DTC P2125, DTC P2127, DTC P2128 Or DTC P2138 >> Diagnosis & Repair (Using OBD-II Scan Tool)
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Diagnosis & Repair (Using OBD-II Scan Tool)

WARNING: This page is about a different car, the 2003 Lexus GS 300. However, it is still accessible from the selected car via links, so may be relevant.
  1. Remove ECM hood. Turn the ignition switch ON. Measure voltage between terminals VC and E2 of ECM connector E5. See Figure. If voltage is 4.5-5.5 volts, go to next step. If voltage is not 4.5-5.5 volts, replace ECM.
  2. Measure voltage between terminals VPA and E2, and VPA2 and E2 of ECM connector E5. See Figure. With pedal released, VPA voltage should be .3-.9 volts and VPA2 voltage should be 1.8-2.7 volts. With pedal depressed, VPA should be 3.2-4.8 volts and VPA2 should be 4.7-5.1 volts.
  3. Check accelerator pedal position sensor. See ACCELERATOR PEDAL POSITION SENSOR in SYSTEM & COMPONENT TESTING - GS300, GS430, IS300 & LS430 article. Replace accelerator pedal position sensor as necessary. If okay, check for open and short in harness and connector in VC, VPA, VPA2 and E2 circuits between ECM and accelerator pedal position sensor.
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