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Diagnosis & Repair

WARNING: This page is about a different car, the 2002 Toyota Avalon. However, it is still accessible from the selected car via links, so may be relevant.
  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 75 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 glove box, near passenger's side kick 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 (Blue/Red 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 - V6 & V8 article. If TP sensor is okay, go to next step. If TP sensor is defective, replace TP sensor. See THROTTLE BODY under FUEL SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - V6 & V8 article.
  5. Remove glove box for access to ECM with electrical connectors still installed on ECM. See Figure. Turn ignition on. Using voltmeter, check voltage between terminals No. 18 (White wire) and No. 23 (Light Green wire) at ECM electrical connector E5 with all electrical connectors installed on ECM with throttle fully closed and fully open. See Figure. This is the E2 and VTA1 terminals on ECM. Voltage should be .3-1.0 volt with throttle fully closed and 2.7-5.2 volts with throttle fully open. If voltages are within specification, replace ECM. If voltages are not within specification, repair open or short in Light Green wire and electrical connectors between TP sensor and ECM. See WIRING DIAGRAMS article.
  6. Remove glove box 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 (Blue/Red wire) and No. 18 (White wire) at ECM electrical connector E5 with all electrical connectors installed on ECM with throttle fully closed and fully open. 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 in Blue/Red wire and electrical connectors between TP sensor and ECM. See WIRING DIAGRAMS article.
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