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 relays-2 and -3.
   Fig 1: Identifying Cooling Fan Relays 1, 2 And 3

   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: Displaying CONSULT-II Active Test Cooling Fan Screen

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

With CONSULT-II 

1. Turn ignition switch OFF.
2. Reconnect cooling fan relays -2 and -3.
3. Turn ignition switch ON.
4. Perform COOLING FAN in ACTIVE TEST mode with CONSULT-II.
   Fig 3: Displaying CONSULT-II Active Test Cooling Fan Screen

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

OK or NG 

1. OK: GO TO  11 .
2. NG: Check cooling fan high speed control circuit. (Go to PROCEDURE B  .)

Without CONSULT-II

1. Disconnect cooling fan relays-2 and -3.
   Fig 4: Identifying Cooling Fan Relays 1, 2 And 3

   Courtesy of NISSAN MOTOR CO., U.S.A.
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.
6. Make sure that cooling fans-1 and -2 operate at low speed.
   Fig 5: Checking Cooling Fan Low Speed Operation

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

Without CONSULT-II

1. Turn ignition switch OFF.
2. Reconnect cooling fan relays-2 and -3.
3. Turn air conditioner switch and blower fan switch OFF.
4. Disconnect engine coolant temperature sensor harness connector.
5. Connect 150ohm resistor to engine coolant temperature sensor harness connector.
6. Restart engine and make sure that cooling fans-1 and -2 operate at high speed.
   Fig 6: Checking Cooling Fan High Speed Operation

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   1. OK: GO TO 6.
   2. NG: Check cooling fan high speed control circuit. (Go to 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: Checking Cooling System For Leak

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Pressure should not drop. 

OK or NG

1. OK: GO TO  8 .
2. NG: GO TO 7.

Check the following for leak.

• Hose
• Radiator
• Water pump (Refer to WATER PUMP )

1. : Repair or replace.

Apply pressure to cap with a tester and check radiator cap relief pressure.

Fig 8: Checking Radiator Cap

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

Radiator cap relief pressure: 

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.

1. Remove thermostat.
2. Check valve seating condition at normal room temperatures.

   It should seat tightly. 

3. Check valve opening temperature and valve lift.
   Fig 9: Checking Thermostat Valve Opening Temperature

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

   Valve opening temperature: 

   82° C (180° F) [standard] 

   Valve lift: 

   More than 8.6 mm/95° C (0.339 in/203° F) 

4. Check if valve is closed at 5° C (9° F) below valve opening temperature. For details, refer to THERMOSTAT .

OK or NG 

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

1. Remove engine coolant temperature sensor.
2. Check resistance between engine coolant temperature sensor terminals 1 and 2 as shown in Figure .

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  .

1. : INSPECTION END