Subaru BRZ 2013 · Service Manual Engine/hybrid system

Cooling fan system (FA20)

Parts location System information Troubleshooting Circuit diagnosis Inspection

COOLING
COOLING FAN SYSTEM (FA20)
PARTS LOCATION
ON-VEHICLE INSPECTION
1. INSPECT COOLING FAN OPERATION AT LOW TEMPERATURES (Below 92 °C (198 °F))
(1) Turn the ignition switch to ON.
(2) Check that the cooling fans stop.
If it does not, check the cooling fan relays and engine coolant temperature sensor, and check whether there is a disconnection or an open circuit between them.
(3) Disconnect the engine coolant temperature sensor connector.
(4) Check that the cooling fans operate.
If it does not, check the fuses, cooling fan relays, ECM and cooling fans, and check for a short circuit between the cooling fan relays and the engine coolant temperature sensor.
(5) Reconnect the engine coolant temperature sensor connector.
2. INSPECT COOLING FAN OPERATION AT HIGH TEMPERATURES (Above 95 °C (203 °F))
(1) Start the engine, and raise the engine coolant temperature to above 95 °C (203 °F).
NOTE:
The engine coolant temperature is detected by the engine coolant temperature sensor on the water outlet.
(2) Check that the cooling fans operate.
If it does not, replace the engine coolant temperature sensor.
CIRCUIT FIGURE
Cooling fan system
Circuit description
With air conditioning
·For the cooling fan, the engine control computer turns ON/OFF the cooling fan relay using the engine coolant temperature, A/C switch, A/C refrigerant pressure, engine speed and vehicle speed signals.
To control the cooling fan motor speed in two stages, the engine control computer turns ON/OFF the fan relay to switch between the series and parallel connections of cooling fan motor circuit.
Without air conditioning
·The engine control computer uses the engine coolant temperature, engine speed, and vehicle speed signals to energize or deenergize the cooling fan relay, thus turns ON/OFF the cooling fan.
Circuit figure
For a circuit figure, refer to .
Inspection steps
NOTE:
Read the freeze frame data using the SSM3. In the freeze frame data, part of the engine running condition at a trouble occurrence is stored and these information is helpful for troubleshooting.
CAUTION:
Check fuses in this circuit before performing the troubleshooting.
1. FAN NO. 1 relay check (power supply voltage)

(1) Remove the FAN NO. 1 relay from the engine compartment relay block.
(2) Measure the voltage between the terminals.
CAUTION:
When measuring the voltage by putting the tester probe etc. on the holder, the holder may be damaged if the probe is pressed against the holder too strong.
Voltage
Inspection terminals
 Inspection conditions
 Standard value
5 (FAN NO. 1) - chassis ground
 Always
 11 to 14V
Captions in illustration
*1
 FAN NO. 1 relay
*a
 Relay not connected
(Engine compartment relay block)
NG
>Repair or replacement of wiring harness or connector

OK▼

2. FAN NO. 3 relay check (power supply voltage)

(1) Remove the FAN NO. 3 relay from the engine compartment relay block.
(2) Measure the voltage between the terminals.
CAUTION:
When measuring the voltage by putting the tester probe etc. on the holder, the holder may be damaged if the probe is pressed against the holder too strong.
Voltage
Inspection terminals
 Inspection conditions
 Standard value
5 (FAN NO. 3) - chassis ground
 Always
 11 to 14V
Captions in illustration
*1
 FAN NO. 3 relay
*a
 Relay not connected
(Engine compartment relay block)
NG
>Repair or replacement of wiring harness or connector

OK▼

3. Engine compartment relay block check (power supply voltage)

(1) Remove the FAN NO. 1 relay, FAN NO. 2 relay and FAN NO. 3 relay from the engine compartment relay block.
(2) Turn the ignition switch to ON.
(3) Measure the voltage between the terminals.
CAUTION:
When measuring the voltage by putting the tester probe etc. on the holder, the holder may be damaged if the probe is pressed against the holder too strong.
Inspection terminals
 Inspection conditions
 Standard value
2 (FAN NO. 1) - chassis ground
 IG ON
 11 to 14V
1 (FAN NO. 2) - chassis ground
 IG ON
 11 to 14V
2 (FAN NO. 3) - chassis ground
 IG ON
 11 to 14V
Captions in illustration
*1
 FAN NO. 1 relay
*2
 FAN NO. 2 relay
*3
 FAN NO. 3 relay
*a
 Relay not connected
(Engine compartment relay block)
NG
>Repair or replacement of wiring harness or connector

OK▼

4. FAN NO. 1 relay unit inspection

(1) Remove the FAN NO. 1 relay from the engine compartment relay block.
(2) Measure the resistance between the terminals.
Resistance
Inspection terminals
 Inspection conditions
 Standard value
3 - 5
 When the battery voltage is not applied to the terminals 1 and 2:
 10 k Ω or more
3 - 5
 When the battery voltage is applied to the terminals 1 and 2:
 Less than 1 Ω
NG
>FAN NO. 1 relay replacement

OK▼

5. FAN NO. 2 relay unit inspection

(1) Remove the FAN NO. 2 relay from the engine compartment relay block.
(2) Measure the resistance between the terminals.
Resistance
Inspection terminals
 Inspection conditions
 Standard value
3 - 4
 When the battery voltage is not applied to the terminals 1 and 2:
 Less than 1 Ω
3 - 4
 When the battery voltage is applied to the terminals 1 and 2:
 10 k Ω or more
3 - 5
 When the battery voltage is not applied to the terminals 1 and 2:
 10 k Ω or more
3 - 5
 When the battery voltage is applied to the terminals 1 and 2:
 Less than 1 Ω
NG
>FAN NO. 2 relay replacement

OK▼

6. FAN NO. 3 relay unit inspection

(1) Remove the FAN NO. 3 relay from the engine compartment relay block.
(2) Measure the resistance between the terminals.
Resistance
Inspection terminals
 Inspection conditions
 Standard value
3 - 5
 When the battery voltage is not applied to the terminals 1 and 2:
 10 k Ω or more
3 - 5
 When the battery voltage is applied to the terminals 1 and 2:
 Less than 1 Ω
NG
>FAN NO. 3 relay replacement

OK▼

7. Check wiring harness and connector (FAN NO. 2 relay - chassis ground)

NOTE:
For the inspection procedure and precautions for wiring harnesses and connectors, refer to .
(1) Remove the FAN NO. 2 relay from the engine compartment relay block.
(2) Measure the resistance between the terminals.
CAUTION:
When measuring the voltage by putting the tester probe etc. on the holder, the holder may be damaged if the probe is pressed against the holder too strong.
Resistance
Inspection terminals
 Inspection conditions
 Standard value
5 (FAN NO. 2) - chassis ground
 Always
 Less than 1 Ω
Captions in illustration
*1
 FAN NO. 2 relay
*a
 Relay not connected
(Engine compartment relay block)
NG
>Repair or replacement of wiring harness or connector

OK▼

8. Cooling fan motor check

(1) Disconnect the cooling fan motor connector.
(2) Connect the battery positive (+) terminal to the terminal 1 of cooling fan motor connector and the negative (-) terminal to the terminal 2.
(3) Check the cooling fan for rotation.
Result :  Rotates
Captions in illustration
*a
 Connector not connected
(Cooling fan motor)
NG
>Cooling fan motor replacement (Refer to )

OK▼

9. Check wiring harness and connector (cooling fan motor - chassis ground)

NOTE:
For the inspection procedure and precautions for wiring harnesses and connectors, refer to .
(1) Disconnect the connector A45 of cooling fan motor.
(2) Measure the resistance between the terminals.
Resistance
Inspection terminals
 Inspection conditions
 Standard value
A45-1 - Chassis ground
 Always
 Less than 1 Ω
NG
>Repair or replacement of wiring harness or connector

OK▼

10. Check wiring harness and connector (cooling fan motor - engine compartment relay block)

NOTE:
For the inspection procedure and precautions for wiring harnesses and connectors, refer to .
(1) Disconnect the connector A45 of cooling fan motor.
(2) Remove the FAN NO. 1 relay and FAN NO. 2 relay from the engine compartment relay block.
Captions in illustration
*1
 FAN NO. 1 relay
 *2
 FAN NO. 2 relay
*a
 Front side of vehicle wiring harness connector
(Connector for connecting cooling fan motor)
 *b
 Relay not connected
(Engine compartment relay block)
(3) Measure the resistance between the terminals.
CAUTION:
When measuring the voltage by putting the tester probe etc. on the holder, the holder may be damaged if the probe is pressed against the holder too strong.
Resistance (open circuit check)
Inspection terminals
 Inspection conditions
 Standard value
A45-2 - 3 (FAN NO. 1 relay)
 Always
 Less than 1 Ω
A45-2 - 4 (FAN NO. 2 relay)
 Always
 Less than 1 Ω
Resistance (short circuit check)
Inspection terminals
 Inspection conditions
 Standard value
A45-2 and 3 (FAN NO. 1 relay) - other terminals and chassis ground
 Always
 10 k Ω or more
A45-2 and 4 (FAN NO. 2 relay) - other terminals and chassis ground
 Always
 10 k Ω or more
NG
>Repair or replacement of wiring harness or connector

OK▼

11. Cooling fan motor NO. 2 check

(1) Disconnect the cooling fan motor NO. 2 connector.
(2) Connect the battery positive (+) terminal to the terminal 1 of cooling fan motor NO. 2 connector and the negative (-) terminal to the terminal 2.
(3) Check the cooling fan for rotation.
Result :  Rotates
Captions in illustration
*a
 Connector not connected
(Cooling fan motor NO. 2)
NG
>Cooling fan motor NO.2 replacement (Refer to )

OK▼

12. Check wiring harness and connector (cooling fan motor NO. 2 - engine compartment relay block)

NOTE:
For the inspection procedure and precautions for wiring harnesses and connectors, refer to .
(1) Disconnect the cooling fan motor NO. 2 connector A46.
(2) Remove the FAN NO. 2 relay and FAN NO. 3 relay from the engine compartment relay block.
Captions in illustration
*1
 FAN NO. 2 relay
 *2
 FAN NO. 3 relay
*a
 Front side of vehicle wiring harness connector
(Connector for connecting cooling fan motor NO. 2)
 *b
 Relay not connected
(Engine compartment relay block)
(3) Measure the resistance between the terminals.
CAUTION:
When measuring the voltage by putting the tester probe etc. on the holder, the holder may be damaged if the probe is pressed against the holder too strong.
Resistance (open circuit check)
Inspection terminals
 Inspection conditions
 Standard value
A46-1 - 3 (FAN NO. 2 relay)
 Always
 Less than 1 Ω
A46-2 - 3 (FAN NO. 3 relay)
 Always
 Less than 1 Ω
Resistance (short circuit check)
Inspection terminals
 Inspection conditions
 Standard value
A46-1 and 3 (FAN NO. 2 relay) - other terminals and chassis ground
 Always
 10 k Ω or more
A46-2 and 3 (FAN NO. 3 relay) - other terminals and chassis ground
 Always
 10 k Ω or more
NG
>Repair or replacement of wiring harness or connector

OK▼

13. Engine compartment relay block check

(1) Remove the FAN NO. 1 relay and FAN NO. 2 relay from the engine compartment relay block.
(2) Measure the resistance between the terminals.
CAUTION:
When measuring the voltage by putting the tester probe etc. on the holder, the holder may be damaged if the probe is pressed against the holder too strong.
Resistance (open circuit check)
Inspection terminals
 Inspection conditions
 Standard value
1 (FAN NO. 1 relay) - 2 (FAN NO. 2 relay)
 Always
 Less than 1 Ω
Resistance (short circuit check)
Inspection terminals
 Inspection conditions
 Standard value
1 (FAN NO. 1 relay) and 2 (FAN NO. 2 relay) - other terminals and chassis ground
 Always
 10 k Ω or more
Captions in illustration
*1
 FAN NO. 1 relay
*2
 FAN NO. 2 relay
*a
 Relay not connected
(Engine compartment relay block)
NG
>Engine compartment relay block replacement

OK▼

14. Check wiring harness and connector (engine control computer - engine compartment relay block)

NOTE:
For the inspection procedure and precautions for wiring harnesses and connectors, refer to .
(1) Disconnect the connector A35 of engine control computer.
(2) Remove the FAN NO. 2 relay and FAN NO. 3 relay from the engine compartment relay block.
(3) Measure the resistance between the terminals.
CAUTION:
When measuring the voltage by putting the tester probe etc. on the holder, the holder may be damaged if the probe is pressed against the holder too strong.
Resistance (open circuit check)
Inspection terminals
 Inspection conditions
 Standard value
A35-11 (FAN1) - 1 (FAN NO. 1 relay)
 Always
 Less than 1 Ω
A35-11 (FAN1) - 2 (FAN NO. 2 relay)
 Always
 Less than 1 Ω
A35-12 (FAN2) - 1 (FAN NO. 3 relay)
 Always
 Less than 1 Ω
Resistance (short circuit check)
Inspection terminals
 Inspection conditions
 Standard value
A35-11 (FAN1) and 1 (FAN NO. 1 relay) - other terminals and chassis ground
 Always
 10 k Ω or more
A35-11 (FAN1) and 2 (FAN NO. 2 relay) - other terminals and chassis ground
 Always
 10 k Ω or more
A35-12 (FAN2) and 1 (FAN NO. 3 relay) - other terminals and chassis ground
 Always
 10 k Ω or more
NG
>Repair or replacement of wiring harness or connector

OK▼
Replacement of engine control computer (Refer to )