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Home >> Mitsubishi >> 2003 >> Lancer Evolution >> Repair and Diagnosis >> External Pages >> Different car >> Section 30 (Engine Controls - Self-Diagnostics) >> Diagnostic Tests >> DTC P0117: Engine Coolant Temperature Sensor Circuit Low Input Or DTC P0118: Engine Coolant Temperature Sensor Circuit High Input >> Diagnostic Procedure
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Diagnostic Procedure

WARNING: This page is about a different car, the 2002 Nissan Maxima and 2002 Infiniti I35. However, it is still accessible from the selected car via links, so may be relevant.
  1. 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.
  2. 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.
  3. 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.
  4. 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) (1) Ohms
68 (20) 2100-2900
122 (50) 680-1000
194 (90) 236-260
(1) Resistance should decrease as temperature increases. See Figure .
Fig 1: Locating ECT Sensor Harness Connector
G00103797Courtesy of NISSAN MOTOR CO., U.S.A.
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