DTC P1120: Secondary Throttle Position Sensor (STPS): Procedure

1. Turn ignition off. Disconnect STPS harness connector. See Figure. Turn ignition on. Measure voltage between ground and STPS harness connector terminal No. 3 (Brown/White wire). If voltage is about 5 volts, go to next step. If voltage is not about 5 volts, repair open or short in Brown/White wire between STPS and Throttle Actuator Control (TAC) module. Retest system.
2. Turn ignition off. Loosen and retighten engine ground bolts. See Figure. Check continuity between engine ground and STPS harness connector terminal No. 1 (Black wire). Also, check circuit for short to voltage. See WIRING DIAGRAMS article. Repair circuit as necessary and retest system. If ground circuit is okay, go to next step.
3. Disconnect TAC Module and ECM harness connectors. See Figure and Fig 1 . Check continuity of Blue wire between ECM harness connector terminal No. 66 and TAC module harness connector terminal No. 4. See Figure and Fig 2 . Also, check circuit for short to ground and short to voltage. Repair circuit as necessary and retest system. If circuit is okay, go to next step.
4. Check continuity of White wire between TAC module harness connector terminal No. 3 and STPS harness connector terminal No. 2. Also, check circuit for short to ground and short to voltage. Repair circuit as necessary and retest system. If circuit is okay, go to next step.
WARNING: Failure to disconnect throttle motor harness connector before touching secondary throttle valve may cause personal injury due to accidental actuation of secondary throttle valve.
5. Disconnect throttle motor harness connector. Remove air intake duct. Measure resistance between STPS terminal No. 1 (Black wire) and No. 2 (White wire), with secondary throttle valve in specified positions. See SECONDARY THROTTLE POSITION SENSOR RESISTANCE  table. If resistance is as specified, go to next step. If resistance is not as specified, replace STPS and retest system.
6. No problem is indicated at this time. Problem may be intermittent. See INTERMITTENTS in TROUBLE SHOOTING - NO CODES article.

SECONDARY THROTTLE POSITION SENSOR RESISTANCE

Secondary Throttle Valve Position	Ohms @ 77°F (25°C)
Fully Closed	About 600
Partially Open	600-4000
Fully Open	About 5000

Fig 1: Locating Throttle Actuator Control (TAC) Module

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

Fig 2: Identifying TAC Module Harness Connector Terminals

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