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DTC P0120 (THV) - Throttle Position (TP) Sensor Circuit Malfunction

NOTE: Refer to illustration for connector and terminal identification. See Figure -Figure .
  1. Turn ignition to OFF. After Connecting SSM or OBD-II scan tool, turn ignition to ON. Turn SSM or OBD-II scan tool to ON. Start Engine. To read TP sensor output, set SSM in function mode F10. If voltage is less than 0.1 volt, go to next step. If voltage is more than 4.9 volts, go to step 4). Check for poor contact at TP sensor connector, ECM connector and coupling connector. Repair as necessary.
  2. With throttle valve fully closed, measure voltage between ECM connector B84, Terminal No. 22 and ground. If voltage is 4.5 volts or more, go to next step. If voltage is more than 4.5 volts while shaking harness and connector, repair poor contact in ECM connector. If voltage remains less than 4.5 volts, replace ECM. Measure signal voltage between ECM connector B84, terminal No. 24 and ground. If voltage is 0.1 volt or less, go to step 3). If voltage is more than 0.1 volt while shaking harness and connector of ECM, repair poor contact in ECM connector. If voltage remains below 0.1 volt, go to next step.
  3. Turn ignition to OFF. Disconnect connectors from TP sensor. Turn ignition to ON. Measure voltage between TP sensor connector E13, terminal No.3 and ground. If voltage is 4.5 volts or more, go to next step. If voltage is less than 4.5 volts, check for open circuit in harness between connector E13, terminal No. 3 and connector B84, terminal No. 22, or; poor contact in TP sensor connector, poor contact in ECM connector or poor contact in coupling connector. If voltage is more than 4.5 volts, turn ignition to OFF. Measure resistance in harness between ECM connector B84, terminal No. 24 and TP sensor connector E13, terminal No. 2. If resistance is more than 10 ohms, repair harness and connector. If resistance is 10 ohms or less, check for open circuit between connector B84, terminal No. 24 and connector E13, terminal No. 2, or poor contact in ECM connector, poor contact in TP sensor connector or poor contact in coupling connector. Measure resistance between TP sensor connector E13, terminal No. 2 and ground. If resistance is 10 ohms or less, repair short circuit in harness between throttle position sensor and ECM connector. If resistance is more than 10 ohms, check for poor contact in TP sensor connector. If poor contact is found, repair as necessary. If contact is okay, replace TP sensor.
  4. Turn ignition to OFF. Disconnect TP sensor. Measure resistance of harness between TP sensor connector E13, terminal No. 1 and ground. If resistance is more than 10 ohms, repair open circuit in harness between TP sensor and ECM connector. If resistance is 10 ohms or less, turn ignition to ON. Measures voltage between TP sensor connector E13, terminal No. 2 and ground. If voltage is 4.9 volts or more, repair short circuit in harness between throttle position sensor and ECM connector. If voltage is less than 4.9 volts, replace TP sensor.
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