On-Vehicle Inspection

WARNING: This page is about a different car, the 2005 Toyota Sienna. However, it is still accessible from the selected car via links, so may be relevant.

INSPECT COOLING FAN OPERATION WHEN COOLANT TEMPERATURE IS 95°C (203°F) BELOW
1. Check that the cooling fan does not operate when turning the ignition switch ON with A/C switch OFF.
2. Check that the cooling fan operates when turning the ignition switch ON with disconnecting the engine coolant temperature sensor connector.
INSPECT COOLING FAN OPERATION WHEN COOLANT TEMPERATURE IS 97°C (207°F) ABOVE
1. Warm up the engine and turn the A/C switch OFF.
2. Check that the cooling fan operates when coolant temperature is 97°C (207°F) above.
3. Check that the cooling fan stops when coolant temperature is 95°C (203°F) below.
Fig 1: Identifying Fan Operation Pattern
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

INSPECT COOLING FAN ECU

Check the cooling fan ECU power source.
1. Disconnect the cooling fan ECU connector.
2. Measure the voltage between the terminals +B and GND.
  Voltage: 9 to 14 V
  
  If the voltage is not specified, check the fusible link, fuse, wire harness and fan relay.
3. Reconnect the connectors.
Fig 2: Checking Cooling Fan ECU Power Source
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
Check the cooling fan operation.
1. Disconnect the cooling fan connectors.
2. Check that the fan operates when applying battery positive to terminal M+ and battery negative to terminal M-.
3. Measure the amperage.
  Fan operation amperage: 10.6 to 16.6 A
  
  Fig 3: Checking Cooling Fan Operation
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
4. Disconnect the cooling fan No. 2 connector.
5. Check that the fan operates when applying battery positive to terminal S+ and battery negative to terminal S-.
6. Measure the amperage.
  Fan No. 2 operation amperage: 5.6 to 11.6 A
  
  It is not as specified, replace the fan motor(s).
7. Reconnect the cooling fan connectors.

Check the wire harness continuity (ECM - cooling fan ECU).

Disconnect the ECM connector and cooling fan ECU connector SI.
Check the wire harness continuity.

If it is not specified, repair or replace the wire harness.

HINT:

Wire harness condition is diagnosed by cooling fan operation.

FAN OPERATION

Cooling fan operation	Wire harness condition
Not operate	Short
Operate continuously	Open

Check the ECM power source.
Check RFC signal generation.
NOTE: Perform this inspection when coolant temperature is 82°C (180°F) below.
1. Connect SST to M+ wire.
  SST 09082-00040, 09083-00350
2. Connect an oscilloscope to terminals RFC and E1 of the ECM.
3. Check the signal generation and measure fan amperage under the condition.

SIGNAL GENERATION CONDITION

Condition	RFC signal generation	Fan amperage	Fan operation
Engine stopped, IG switch ON	-	-	Not operate
Engine idling, A/C OFF	-	-	Not operate
Engine idling, A/C ON	Indication 1	7 to 11 A	Operate
Engine idling, Disconnect engine coolant temperature sensor connector	Indication 2	10 to 19 A	Operate (High speed)

Oscilloscope indication:

HINT:

If RFC signal is not specified, replace the ECM.
When the fan amperage has a problem in spite that the RFC signal has no problem, replace the cooling fan ECU.

Fig 4: Identifying Oscilloscope Indication