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Home >> Toyota >> 2000 >> RAV4 Base, AWD, Standard >> Repair and Diagnosis >> External Pages >> Different car >> Section 21 (Engine Control System Self-Diagnostics) >> Diagnostic Tests >> DTC P0120: Throttle Position (TP) Sensor Circuit >> Diagnosis & Repair
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Diagnosis & Repair

WARNING: This page is about a different car, the 2000 Toyota Celica. However, it is still accessible from the selected car via links, so may be relevant.
  1. Connect scan tool to Data Link Connector (DLC) No. 3. See Figure. Turn ignition on. Using scan tool, monitor throttle valve opening percentage. Opening percentage should be approximately 10 percent with fully closed throttle, and should be approximately 80 percent with throttle fully open (WOT). If percentages are as specified, problem is intermittent. Check component and ECM connections. If percentages are not as specified, go to next step.
  2. Turn ignition off. Disconnect TP sensor harness connector. Turn ignition on. Using DVOM, measure voltage between ground and Red wire terminal (terminal No. 1 on 1ZZ-FE; terminal No. 2 on 2ZZ-GE) at TP sensor harness connector. If voltage is 4.5-5.5 volts, go to next step. If voltage is not 4.5-5.5 volts, go to step  5.
  3. Check TP sensor. See ENGINE SENSORS & SWITCHES in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. If problem exists, replace TP sensor. If problem does not exist, go to next step.
  4. Access ECM in driver's side of engine compartment, next to battery. Turn ignition on. Using DVOM, backprobe ECM harness connector and measure voltage between terminals No. 18 (Brown wire) and No. 23 (Black/White wire) at ECM harness connector E4. See Figure. Voltage should be .3-.8 volt with throttle fully closed and 3.2-4.9 volts with throttle fully open (WOT). If voltage is as specified, replace ECM. If voltage is not as specified, repair open or short in wiring between TP sensor and ECM. See WIRING DIAGRAMS article.
  5. Access ECM in driver's side of engine compartment, next to battery. Turn ignition on. Using DVOM, backprobe ECM harness connector and measure voltage between terminals No. 2 (Red wire) and No. 18 (Brown wire) at ECM harness connector E4. See Figure. Voltage should be 4.5-5.5 volts. If voltage is as specified, repair open in Red wire between TP sensor and ECM. If voltage is not as specified, replace ECM.
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