DTC P0120: Throttle Position (TP) Sensor

Check Power Supply - Turn ignition off. Disconnect TP sensor harness connector. Turn ignition on. Measure voltage between TP sensor connector terminal No. 1 (Green wire) and ground. If voltage is approximately 5 volts, go to next step. If voltage is not as specified, repair harness or connectors as necessary.
Check Ground Circuit - Turn ignition off. Verify harness continuity between TP sensor connector terminal No. 3 (Orange/Blue wire) and engine ground. If continuity is present, go to next step. If continuity is not present, repair harness or connectors as necessary.
Check Input Signal Circuit - Disconnect ECM harness connector. Verify harness continuity between TP sensor connector terminal No. 2 (Black wire) and ECM connector terminal No. 23. If continuity is present, go to next step. If continuity is not present, repair harness or connectors as necessary.
Check Component - Leave TP sensor disconnected. While opening and closing throttle, check resistance across TP sensor connector terminal No. 2 and No. 3. See Fig 1. See THROTTLE POSITION SENSOR RESISTANCE table. If resistance is not as specified, adjust TP sensor. See ADJUSTMENTS article. If resistance is still not as specified after adjustment, replace TP sensor.

THROTTLE POSITION SENSOR RESISTANCE ⁽¹⁾

Throttle Position

Ohms

Fully Closed

About 500

Partially Opened

500-4000

Fully Open

About 4000

⁽¹⁾	Ensure resistance changes when opening and closing throttle.

Fig 1: Testing Throttle Position (TP) Sensor

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