Diagnostic Procedure
- 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 (Yellow wire). If voltage is about 5 volts, go to next step. If voltage is not about 5 volts, repair open or short between ECM and ECT sensor.
- Turn ignition off. Check continuity between engine ground and ECT sensor harness connector terminal No. 2 (Black wire). Continuity should exist. Also, check circuit for short to voltage. If problem is found, repair as necessary. If problem is not found, go to next step.
- Remove ECT sensor, and place in heated water. Measure resistance between sensor terminals, with water at specified temperatures. See ENGINE COOLANT TEMPERATURE SENSOR RESISTANCE
table. If resistance is as specified, go to next step. If resistance is not as specified, replace ECT sensor.
- No problem is indicated at this time. Problem may be intermittent. See INTERMITTENTS
in TROUBLE SHOOTING - NO CODES article.
ENGINE COOLANT TEMPERATURE SENSOR RESISTANCE
| Temperature - °F (°C) |
Ohms |
| 68 (20) |
2100-2900 |
| 122 (50) |
680-1000 |
| 194 (90) |
236-260 |
Courtesy of NISSAN MOTOR CO., U.S.A.