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 ECT 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.
  
  Fig 2: Checking Voltage Between ECT Terminal 1 & Ground
  Courtesy of NISSAN MOTOR CO., U.S.A.
  
  Voltage: Approximately 5V
OK or NG
1. OK: GO TO 2.
2. NG: Repair or replace harness or connectors.
CHECK ETC SENSOR GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Disconnect TCM harness connector (A/T models).
4. Check harness continuity between ECT terminal 2 and ECM terminal 67, TCM terminal 42 (A/T models). Refer to WIRING DIAGRAM .
  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 TCM and engine coolant temperature sensor (A/T models)
- Harness for open or short between ECM and engine coolant temperature sensor
  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 engine coolant temperature sensor.
CHECK INTERMITTENT INCIDENT
Perform "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT ".
1. INSPECTION END