Procedure "A"

Turn ignition off. Loosen and retighten 2 engine ground bolts. See Figure. Disconnect TP sensor harness connector. See Fig 1. Turn ignition on. Measure voltage between ground and TP sensor harness connector terminal No. 4 (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 ECM and TP sensor. Retest system.
Turn ignition off. Check continuity between engine ground and TP sensor harness connector terminal No. 2 (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.
Disconnect ECM harness connector. See Figure. Check continuity of Green wire between ECM harness connector terminal No. 63 and TP sensor harness connector terminal No. 1. See Figure. 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.

CAUTION: DO NOT use ECM ground terminals when measuring voltage.

Reconnect all harness connectors. Start engine and warm to normal operating temperature. Remove vacuum hose from throttle opener. Using a hand vacuum pump, apply vacuum to throttle opener until throttle drum no longer contacts throttle opener rod. Turn ignition on. Measure voltage between ground and ECM terminal No. 63 by backprobing, with throttle in specified positions. See Figure. See THROTTLE POSITION (TP) SENSOR VOLTAGE table. If voltage is as specified, go to next step. If voltage is not as specified, adjust TP sensor, if possible. See ON-VEHICLE ADJUSTMENTS article. If TP sensor can not be adjusted, replace TP sensor and retest system.
No problem is indicated at this time. Problem may be intermittent. See INTERMITTENTS in TROUBLE SHOOTING - NO CODES article.

THROTTLE POSITION (TP) SENSOR VOLTAGE

Fig 1: Locating Throttle Position (TP) Sensor Connector

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