Throttle Position Sensor (TPS) & Idle Switch

Throttle position sensor and idle switch are a combined assembly located on side of throttle body. Idle switch connector is located on sensor; TPS connector is a separate harness connected to sensor. Warm engine to operating temperature. On Q45, ensure fast idle cam is fully released. On all models, turn ignition off. Disconnect TPS at harness. Connect ohmmeter between terminals No. 5 and 6 on sensor side of harness. See Fig 1 .

Fig 1: Testing Throttle Position Sensor
Courtesy of NISSAN MOTOR CO., U.S.A.
On G20, resistance should be approximately 2000 ohms with throttle closed. With throttle completely open, resistance should be approximately 10,000 ohms. If sensor does not respond as indicated, adjust TPS. See ADJUSTMENTS article in the ENGINE PERFORMANCE Section.
On M30, resistance should be approximately 1000 ohms with throttle closed. With throttle completely open, resistance should be approximately 9000 ohms. If sensor does not respond as indicated, adjust TPS. See ADJUSTMENTS article in the ENGINE PERFORMANCE Section.
On Q45, resistance should be about 400 ohms with throttle closed. With throttle completely open, resistance should be about 5000 ohms.
As throttle angle is slowly changed, resistance should change smoothly, with no skips or sudden changes indicated on ohmmeter. If sensor does not respond as indicated, replace TPS.
On M30 and Q45, reconnect TPS harness connector. Disconnect idle switch connector at TPS. Connect ohmmeter leads between terminals No. 2 and 3 of idle switch harness to sensor.
With throttle fully closed, resistance should be zero ohms. With throttle slightly open, resistance should be infinite. If sensor does not respond as indicated, replace TPS.