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Home >> Toyota >> 2002 >> RAV4 L, AWD, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System Self-Diagnostics >> Diagnostic Tests >> DTC P0120: Throttle Position Sensor Circuit >> Diagnosis & Repair
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Diagnosis & Repair

  1. Connect Toyota hand-held tester or scan tool to Data Link Connector (DLC) No. 3 at driver's side of instrument panel. See Figure. Turn ignition on and then turn hand-held tester or scan tool on.
  2. Using hand-held tester or scan tool, read throttle valve opening percentages with throttle fully closed and fully open. Throttle valve opening percentage should be approximately 10 percent with throttle fully closed and approximately 70 percent with throttle fully open. If throttle valve opening percentages are not within specification, go to next step. If throttle valve opening percentages are within specification, problem is intermittent. Check for defective connections or intermittent problem in wiring between TP sensor and ECM. ECM is located behind passenger's side kick panel, just below instrument panel. See Figure.
  3. Turn ignition off. Disconnect electrical connector at TP sensor. Turn ignition on. Using voltmeter, check voltage between body ground and terminal No. 1 (Yellow wire) at electrical connector for TP. If voltage is 4.5-5.5 volts, go to next step. If voltage is not 4.5-5.5 volts, go to step  6.
  4. Check TP sensor. See THROTTLE POSITION SENSOR under ENGINE SENSORS & SWITCHES in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. If TP sensor is okay, go to next step. If TP sensor is defective, replace TP sensor.
  5. Remove glove box and passenger's side kick panel (if necessary) for access to ECM with electrical connectors still installed on ECM. See Figure. Turn ignition on. Using voltmeter, check voltage between terminals No. 18 (Brown wire) at ECM electrical connector E5 and No. 24 (Blue/Red wire) at ECM electrical connector E4 with all electrical connectors installed on ECM with throttle fully closed and fully open. See Figure. This is the E2 and VTA terminals on ECM. Voltage should be .3-1.0 volt with throttle fully closed and 3.2-4.9 volts with throttle fully open. If voltages are within specification, replace ECM. If voltages are not within specification, repair open or short in Brown wire and/or Blue/Red wire and electrical connectors between TP sensor and ECM. See WIRING DIAGRAMS article.
  6. Remove glove box and passenger's side kick panel (if necessary) for access to ECM with electrical connectors still installed on ECM. See Figure. Ensure ignition is on. Using voltmeter, check voltage between terminals No. 2 (Yellow wire) and No. 18 (Brown wire) at ECM electrical connector E5 with all electrical connectors installed on ECM. See Figure. This is the VC and E2 terminals on ECM. Voltage should be 4.5-5.5 volts. If voltage is not within specification, replace ECM. If voltage is within specification, repair open or short in Yellow wire and electrical connectors between TP sensor and ECM. See WIRING DIAGRAMS article.
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