Diagnostic Procedure: Notes

Do you have CONSULT-II?

Yes or No 

• Yes : GO TO 2.
• No : GO TO  4.

With CONSULT-II 

1. Disconnect cooling fan relay-2.
   Fig 1: Identifying Cooling Fan Relays

   Courtesy of NISSAN MOTOR CO., U.S.A.
2. Turn ignition switch ON.
3. Perform "COOLING FAN" in "ACTIVE TEST" mode with CONSULT-II.
   Fig 2: CONSULT-II Display - ACTIVE TEST, COOLING FAN

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4. Make sure that cooling fans-1 and -2 operate at low speed.

OK or NG 

• OK : GO TO 3.
• NG : Check cooling fan low speed control circuit. (Go to PROCEDURE A, PROCEDURE 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.
   Fig 3: CONSULT-II Display - ACTIVE TEST, COOLING FAN

   Courtesy of NISSAN MOTOR CO., U.S.A.
5. Make sure that cooling fan-1 operates at high speed.

OK or NG 

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

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: Locating Cooling Fan Relays

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6. Make sure that cooling fans-1 and -2 operate at low speed.

Fig 5: Cooling Fans Operating At Low Speed

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OK or NG 

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

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

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6. Restart engine and make sure that cooling fan-1 operates at high speed.

OK or NG 

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

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

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

Fig 7: Pressure Testing Cooling System Using Tester

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OK or NG 

• OK : GO TO  8.
• NG : GO TO 7.

Check the following for leak.

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

Apply pressure to cap with a tester.

• Radiator cap relief pressure: 
  • 59 - 98 kPa (0.6 - 1.0 kg/cm ²  , 9 - 14 psi) 
Fig 8: Applying Pressure To Radiator Cap Using Tester
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OK or NG 

• OK : GO TO 9.
• NG : Replace radiator cap.

1. Check valve seating condition at normal room temperatures.

   It should seat tightly. 

2. Check valve opening temperature and valve lift.
   • Valve opening temperature: 
     • 76.5°C (170°F) [standard] 
   • Valve lift: 
     • 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.

Fig 9: Checking Thermostat Valve

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For details, refer to "THERMOSTAT AND THERMOSTAT HOUSING ".

OK or NG 

• OK : GO TO 10.
• NG : Replace thermostat.

Refer to "COMPONENT INSPECTION ".

OK or NG 

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

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

• : INSPECTION END