Cooling Fan Control System Inspection

Connect the M-MDS to the DLC-2.
Perform the KOEO or KOER self test and verify that DTCs P0117:00, P0118:00, P0480:00 and/or P0481:00 are not shown using the KOEO and/or KOER self test. (See KOEO/KOER SELF TEST .)
- If DTCs P0117:00, P0118:00, P0480:00 and/or P0481:00 are shown, perform the applicable DTC troubleshooting procedure. (See DTC P0117:00 .) (See DTC P0118:00 .) (See DTC P0480:00 .) (See DTC P0481:00 .)
Start the engine and let it at idle with ECT is below 97 °C {207 °F} .

Verify that the cooling fans are not operating when A/C switch and fan switch are turned off.

If the cooling fan is operating, inspect for the following based on cooling fans status:

Cooling fan status		Inspection item
Cooling fan No.1	Cooling fan No.2	Inspection item
Low	Low	Cooling fan relay No.1 (Stuck close)
High	High	PCM PID AC_REQ is always ON. Climate control unit CAN communication
Stop	High	Cooling fan relay No.3 (Stuck close)

Using the M-MDS simulation function, turn FAN1 from the off position to the ON position, and verify that cooling fans No.1 and No.2 operate at low speed.

If the operation could not be confirmed, inspect for the following based on cooling fans status:

Cooling fan status

Inspection item

Cooling fan No.1

Cooling fan No.2

Stop

Cooling fan relay No.1 (Stuck open)
Cooling fan No.1 (Internal circuit open)
Cooling fan No.2 (Internal circuit open)
Wiring harness in battery-cooling fan relay No.1-cooling fan No.1 (Open circuit, Fuse is blown by short to ground)
Wiring harness in cooling fan No.1-cooling fan relay No.3-cooling fan No.2 (Open circuit)
Wiring harness in cooling fan No.2-body ground (Open circuit)

High

Stop

Cooling fan relay No.2 (Stuck close)
Wiring harness in cooling fan No.1-cooling fan relay No.3-cooling fan No.2 (Short to ground)⁽¹⁾

⁽¹⁾	The fuse between battery and cooling fan relay No.3 may be burnt out.

Using the M-MDS simulation function, turn FAN1 and FAN2 from the off position to the ON position, and verify that cooling fans No.1 and No.2 operate at high speed.
- If the operation could not be confirmed, inspect for the following based on cooling fans status:

Cooling fan status		Inspection item
Cooling fan No.1	Cooling fan No.2	Inspection item
Stop	High	Cooling fan relay No.2 (Stuck open) Wiring harness in cooling fan relay No.2-body ground (Open circuit)
High	Stop	Cooling fan relay No.3 (Stuck open) Wiring harness in battery-cooling fan relay No.3 (Open circuit, Fuse is blown by short to ground)