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Home >> Mitsubishi >> 2000 >> Eclipse GS, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Diagnostic Tests >> DTC P0120: Throttle Position (TP) Sensor Circuit Malfunction >> Diagnostic Procedure
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Diagnostic Procedure

  1. Connect MUT-II Scan Tool (MB991502) to OBD-II Data Link Connector (OBD-II DLC), located below center of instrument panel. Turn ignition on. Using scan tool, check data list item No. 14 (throttle position sensor). With throttle valve in idle position, voltage should be 300-1000 millivolts (2.4L) or 535-735 millivolts (3.0L). With throttle valve in fully open position, voltage should be 4.5-5.5 volts. If voltages are as specified, problem is intermittent. See INTERMITTENT DTCS  under CIRCUIT TESTS. If voltages are not as specified, go to next step.
  2. Turn ignition off. Disconnect TP sensor 4-pin connector. Check resistance between TP sensor connector terminals No. 1 and 4 (component side). Resistance should be 3.5-6.5 k/ohms. Check resistance between TP sensor connector terminals No. 1 and 3 (component side) while slowly opening throttle valve from idle position to fully open position. Resistance should change smoothly in proportion to opening of valve. If either resistance is not as specified, replace TP sensor, then go to step  7 . If resistances are as specified, go to next step.
  3. Turn ignition on. Check voltage between ground and TP sensor connector terminal No. 4. Voltage should be 4.8-5.2 volts. Turn ignition off. Check resistance between ground and TP sensor connector terminal No. 1. Resistance should be less than 2 ohms. If voltage and resistance are as specified, go to next step. If voltage or resistance is not as specified, go to step  5 .
  4. Check TP sensor connector. Repair as necessary, then go to step  7 . If connectors are okay, go to next step.
  5. Check ECM connectors, or PCM connectors. Repair as necessary, then go to step  7 . If connector(s) are okay, go to next step.
  6. Check wiring between TP sensor and ECM/PCM. Repair as necessary, then go to next step. If wiring is okay, replace ECM/PCM, then go to next step.
  7. Remove all test equipment and install all disconnected/removed components. Using scan tool, clear DTCs. Test drive vehicle following other monitor drive cycle pattern. See OBD-II DRIVE CYCLES under VERIFYING REPAIRS in SELF-DIAGNOSTICS - INTRODUCTION article. Check for DTCs. Confirm DTC P0120 does not reset. See VERIFYING REPAIRS in SELF-DIAGNOSTICS - INTRODUCTION article.
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