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Home >> Mitsubishi >> 1998 >> Montero >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes >> DTC Tests >> DTC P0120: Throttle Position (TP) Sensor Circuit Malfunction

DTC P0120: Throttle Position (TP) Sensor Circuit Malfunction

NOTE: For terminal identification, see TERMINAL IDENTIFICATION . For circuit and wire color identification, see WIRING DIAGRAMS article.
  1. Turn ignition on. Using scan tool, read closed TP switch state (item 26). With throttle at idle, scan tool should display ON. With throttle slightly open, scan tool should display OFF. If closed TP switch tests as specified, go to next step. If switch does not test as specified, go to P0510  test.
  2. Using scan tool, read TP sensor voltage (item 14). Turn ignition on, engine off. With throttle at idle, voltage should be 0.3-1.0 volt. With throttle fully open, voltage should be 4.5-5.5 volts. Turn ignition off. If TP sensor does not test as specified, go to next step. If sensor tests as specified, fault is intermittent. See INTERMITTENT DTCS .
  3. Disconnect TP sensor connector. Using DVOM, check resistance between TP sensor terminals No. 1 and 4. Resistance should be 3500-6500 ohms. Check resistance between TP sensor terminals No. 2 and 4 on 2.4L or 1 and 3 on 3.0L. While monitoring DVOM, slowly open throttle from idle to fully open position. Resistance should change smoothly as throttle opens. If TP sensor tests as specified, go to next step. If sensor does not test as specified, replace sensor. Go to step 9).
  4. Disconnect TP sensor connector. Turn ignition on. Using DVOM, check voltage between ground and TP sensor connector terminal No. 1 on 2.4L or 4 on 3.0L. Voltage should be 4.8-5.2 volts. Turn ignition off. Using DVOM, check for continuity between ground and TP sensor connector terminal No. 4 on 2.4L or 1 on 3.0L. Continuity should exist. If voltage is as specified and continuity exists, go to next step. If voltage is not as specified or continuity does not exist, go to step 7).
  5. Inspect connectors and wiring harness between TP sensor and PCM. Repair as necessary. Go to step 9). If connectors and wiring harness are okay, go to next step.
  6. Inspect TP sensor connector for damage. Repair or replace connector as necessary. Go to step 9). If connector is okay, go to step 8).
  7. Inspect connectors and wiring harness between TP sensor and PCM. Repair as necessary. Go to step 9). If connectors and wiring harness are okay, go to next step.
  8. Inspect PCM connector for damage. Repair or replace connector as necessary. Go to next step. If connector is okay, replace PCM. Go to next step.
  9. Road test vehicle and attempt to duplicate conditions that caused original complaint. Recheck for DTCs. If no DTCs are displayed, test is complete.
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