Diagnostic Procedure
WARNING: This page is about a different car, the 2002 Nissan Sentra. However, it is still accessible from the selected car via links, so may be relevant.
- Turn ignition off. Disconnect ECT sensor harness connector. See Fig 1. Turn ignition on. Measure voltage between ground and ECT sensor harness connector terminal No. 1 (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 ECT and ECM, then retest system.
- Turn ignition off. Check continuity between ground and ECT sensor harness connector terminal No. 2 (Black wire). Continuity should exist. Also, check circuit for short to voltage. See 2.5L under ENGINE PERFORMANCE inSYSTEM WIRING DIAGRAMS in ELECTRICAL article. Repair circuit as necessary and retest system. If circuit is okay, go to next step.
- Measure resistance between ECT sensor terminals (component side), with sensor at specified temperatures. See ECT SENSOR RESISTANCE . If resistance is as specified, go to next step. If resistance is not as specified, replace ECT sensor and retest system.
- If DTC P0115 is present, go to next step. If DTC P0125 is present, allow engine to cool until coolant temperature is less than 170°F (77°C). Start engine. Check thermostat operation. If thermostat is operating properly, go to next step. If thermostat is malfunctioning, replace thermostat and retest system.
- No problem is indicated at this time. Problem may be intermittent. See INTERMITTENTS in TROUBLESHOOTING - NO CODES article.
ECT SENSOR RESISTANCE
| Temperature - °F (°C) | (1) Ohms | ||
|---|---|---|---|
| 68 (20) | 2100-2900 | ||
| 122 (50) | 680-1000 | ||
| 194 (90) | 236-260 | ||
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