Diagnostic Procedure

CHECK ETC SENSOR POWER SUPPLY CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect engine coolant temperature (ECT) sensor harness connector.
3. Turn ignition switch ON.
  
  Fig 1: Disconnecting Engine Coolant Temperature Sensor Harness Connector
  Courtesy of NISSAN MOTOR CO., U.S.A.
4. Check voltage between ECT terminal 1 and ground with CONSULT-II or tester.
  1. Voltage: Approximately 5V
OK or NG
1. OK: GO TO 2.
2. NG: Repair open circuit or short to ground or short to power in harness or connectors.
Fig 2: Checking Voltage Between ECT Terminal 1 And Ground With Consult-II Or Tester
Courtesy of NISSAN MOTOR CO., U.S.A.
CHECK ETC SENSOR GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Disconnect TCM harness connector.
4. Check harness continuity between ECT sensor terminal 2 and ECM terminal 67, TCM terminal 42.
  Refer to WIRING DIAGRAM .
  1. Continuity should exist.
5. Also check harness for short to ground and short to power.
OK or NG
1. OK: GO TO 4.
2. NG: GO TO 3.
DETECT MALFUNCTIONING PART
Check the following.
- Harness for open or short between ECT sensor and ECM
- Harness for open or short between ECT sensor and TCM
1. : Repair open circuit or short to ground or short to power in harness or connectors.
CHECK ENGINE COOLANT TEMPERATURE SENSOR
Refer to COMPONENT INSPECTION .

OK or NG
1. OK: GO TO 5.
2. NG: Replace ECT sensor.
CHECK INTERMITTENT INCIDENT
Perform TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT .
1. : INSPECTION END