Diagnostic Procedure: Notes

Do you have CONSULT-II?

Yes or No 

1. Yes: GO TO 2.
2. No: GO TO  4.

With CONSULT-II 

1. Disconnect cooling fan relay-2.
2. Turn ignition switch ON.
   Fig 1: Disconnecting Cooling Fan Relay-2

   Courtesy of NISSAN MOTOR CO., U.S.A.
3. Perform "COOLING FAN" in "ACTIVE TEST" mode with CONSULT-II.
4. Make sure that cooling fans-1 and -2 operate at low speed.

OK or NG 

1. OK: GO TO 3.
2. NG: Check cooling fan low speed control circuit. (Go to PROCEDURE A .)

Fig 2: Displaying ACTIVE TEST Mode (1 Of 2)

Courtesy of NISSAN MOTOR CO., U.S.A.

With CONSULT-II 

1. Turn ignition switch OFF.
2. Reconnect cooling fan relay-2.
3. Turn ignition switch ON.
4. Perform "COOLING FAN" in "ACTIVE TEST" mode with CONSULT-II.
5. Make sure that cooling fan-1 operates at high speed.

OK or NG 

1. OK: GO TO  6.
2. NG: Check cooling fan high speed control circuit. (Go to PROCEDURE B .)

Fig 3: Displaying ACTIVE TEST Mode (2 Of 2)

Courtesy of NISSAN MOTOR CO., U.S.A.

Without CONSULT-II 

1. Disconnect cooling fan relays-2.
2. Start engine and let it idle.
3. Set temperature lever at full cold position.
4. Turn air conditioner switch ON.
5. Turn blower fan switch ON.
   Fig 4: Identifying Cooling Fan Relays-2

   Courtesy of NISSAN MOTOR CO., U.S.A.
6. Make sure that cooling fans-1 and -2 operate at low speed.

OK or NG 

1. OK: GO TO 5.
2. NG: Check cooling fan low speed control circuit. (Go to PROCEDURE A .)

Fig 5: Identifying Cooling Fans

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Without CONSULT-II 

1. Turn ignition switch OFF.
2. Reconnect cooling fan relay-2.
3. Turn air conditioner switch and blower fan switch OFF.
4. Disconnect engine coolant temperature sensor harness connector.
5. Connect 150Ω resistor to engine coolant temperature sensor harness connector.
6. Restart engine and make sure that cooling fan-1 operates at high speed.

OK or NG 

1. OK: GO TO 6.
2. NG: Check cooling fan high speed control circuit. (Go to PROCEDURE B .)

Fig 6: Connecting 150Ω Resistor To Engine Coolant Temperature Sensor Harness Connector

Courtesy of NISSAN MOTOR CO., U.S.A.

Apply pressure to the cooling system with a tester, and check if the pressure drops.

1. Testing pressure: 157 kPa (1.6 kg/cm ² , 23 psi) 

OK or NG 

1. OK: GO TO  8.
2. NG: GO TO 7.

Fig 7: Applying Pressure To Cooling System

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Check the following for leak.

• Hose
• Radiator
• Water pump (Refer to WATER PUMP .)
  1. Repair or replace.

Apply pressure to cap with a tester.

1. Radiator cap relief pressure: 
   1. 59 - 98 kPa (0.6 - 1.0 kg/cm ² , 9 - 14 psi) 

OK or NG 

1. OK: GO TO 9.
2. NG: Replace radiator cap.

Fig 8: Applying Pressure To Cap Using Tester

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1. Check valve seating condition at normal room temperatures.

   It should seat tightly. 

2. Check valve opening temperature and valve lift.
   1. Valve opening temperature: 
      1. 76.5°C (170°F) [standard] 
   2. Valve lift: 
      1. More than 9 mm/90°C (0.35 in/194°F) 
3. Check if valve is closed at 5°C (9°F) below valve opening temperature.

For details, refer to THERMOSTAT AND THERMOSTAT HOUSING .

Fig 9: Checking Thermostat

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OK or NG 

1. OK: GO TO 10.
2. NG: Replace thermostat.

Refer to COMPONENT INSPECTION .

OK or NG 

1. OK: GO TO 11.
2. NG: Replace engine coolant temperature sensor.

If the cause cannot be isolated, go to MAIN 12 CAUSES OF OVERHEATING .