MPI – Troubleshooting
13-41
INSPECTION PROCEDURE 30 <EVOLUTION-VI>
Fan motor relay system (Radiator fan, A/C condenser fan)
Probable cause
The engine-ECU turns on/off the built-in power transistor to control the fan motor
relay.
D Malfunction of the fan motor relay
D Malfunction of the fan motor
D Malfunction of thermostat
D Improper connector contact, open or short-circuited
harness wire
D Malfunction of engine-ECU
NG
Check the engine coolant temperature sensor. (Refer to P.13-10,
INSPECTION PROCEDURE FOR DIAGNOSIS CODE 21.)
OK
Replace the engine-ECU.
NG
MUT-II Data list
21 Engine coolant temperature sensor
OK: The engine coolant temperature agrees with the reading
of MUT-II when measured with the engine idling in warm
condition.
OK
Check the thermostat.
NG
Replace
OK
Check trouble symptom.
OK
Check the following connector: B-60
NG
Repair
NG
Check the A/C condenser fan circuit. (Refer to Electrical Wirings.)
NG
Measure at the engine-ECU connector B-60.
D Disconnect the connector, and measure at the harness side.
D Check the A/C condenser fan for operating condition.
(Ignition switch: ON)
OK: A/C condenser fan is stationary.
D Voltage between each of 32 and 34 and earth
(Ignition switch: ON)
OK: System voltage
D Short the terminal 32 to earth. (Ignition switch: ON)
OK: A/C condenser fan operates at high speed.
D Short the terminal 34 to earth. (Ignition switch: ON)
OK: A/C condenser fan operates at low speed.
Check trouble symptom.
OK
OK
Check the following connector: B-59
NG
Repair
Measure at the engine-ECU connector B-59.
D Disconnect the connector, and measure at the harness side.
D Check the radiator fan for operating condition.
(Ignition switch: ON)
OK: Radiator fan is stationary.
D Voltage between each of 20 and 21 and earth
(Ignition switch: ON)
OK: System voltage
D Short the terminal 20 to earth.
(Ignition switch: ON)
OK: Radiator fan operates at high speed.
D Short the terminal 21 to earth.
(Ignition switch: ON)
OK: Radiator fan operates at low speed.
NG
Check the radiator fan circuit. (Refer to Electrical Wirings.)
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