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Home >> Nissan-Datsun >> 2003 >> Sentra Limited >> Repair and Diagnosis >> External Pages >> Different car >> Section 112 (Engine Controls Self-Diagnostics - Pathfinder) >> Diagnostic Tests >> DTC P0117: Engine Coolant Temperature Sensor - Low Input Or DTC P0118: Engine Coolant Temperature Sensor - High Input >> Diagnostic Procedure

Diagnostic Procedure

WARNING: This page is about a different car, the 2003 Nissan Pathfinder. However, it is still accessible from the selected car via links, so may be relevant.
  1. Turn ignition off. Disconnect ECT sensor harness connector. ECT sensor is located left side if engine block. Turn ignition on. Measure voltage between ground and ECT sensor harness connector terminal No. 1 (Light Green/Red wire). Voltage should be about 5 volts. If voltage is as specified, leave harness connector disconnected and go to step  3. If voltage is not as specified, go to next step.
  2. Check following:
    • Check for poor, loose, corroded or damaged terminal connections in ECT sensor harness connector.
    • Check for open or short in circuits between ECM and ECT sensor harness connector. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL.
    If problem is found, repair as necessary. If no problem is found, go to next step.
  3. Turn ignition off. Disconnect ECM 116-pin harness connector. ECM is located behind instrument panel lower cover. See Figure. Check continuity between ECM harness connector terminal No. 67 and ECT sensor harness connector terminal No. 2. Continuity should exist. Also check circuit for short to voltage. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. If no problem is found, go to next step. If problem is found, repair as necessary.
  4. Remove ECT sensor from engine. Place ECT sensor in heated water. Measure resistance between sensor terminals No. 1 and 2, 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 and retest system.
    ENGINE COOLANT TEMPERATURE SENSOR RESISTANCE

    Temperature - °F (°C) (1) Ohms
    68 (20) 2100-2900
    122 (50) 680-1000
    194 (90) 236-260
    (1) Resistance should decrease as temperature increases. See Figure.
  5. No problem is indicated at this time. Problem may be intermittent. See INTERMITTENTS in TROUBLE SHOOTING - NO CODES article.
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