DTC P0120 - Throttle Position Sensor (TPS)

1. Check Power Supply
   
   Turn ignition off and disconnect TPS harness connector. See Fig 1. Turn ignition on. Measure voltage between TPS connector terminal "3" (Red/White wire) and ground. See Fig 2. If voltage is approximately 5 volts, go to next step. If voltage is not as specified, repair harness or connectors as necessary.
2. Check Ground Circuit
   
   Turn ignition off. Verify harness continuity between TPS connector terminal "1" (Black/Yellow wire) and engine ground. See Fig 3. If continuity is present, go to next step. If continuity is not present, repair harness or connectors as necessary.
3. Check Input Signal Circuit
   
   Disconnect ECM harness connector. Verify harness continuity between ECM connector terminal No. 23 (White wire) and TPS connector terminal "2". See Fig 4. If continuity is present, go to next step. If continuity is not present, repair harness or connectors as necessary.
4. Check Component
   
   Inspect TPS. See SYSTEM/COMPONENT TESTS article. Replace TPS if necessary and perform FINAL CHECK .

Fig 1: Locating TP Sensor & Harness Connector (Q45)

Courtesy of NISSAN MOTOR CO., U.S.A.

Fig 2: DTC P0120, Checking Power Supply (Q45)

Courtesy of NISSAN MOTOR CO., U.S.A.

Fig 3: DTC P0120, Checking Ground Circuit (Q45)

Courtesy of NISSAN MOTOR CO., U.S.A.

Fig 4: DTC P0120, Checking Input Signal Circuit (Q45)

Courtesy of NISSAN MOTOR CO., U.S.A.