MPI – Troubleshooting
13-40
INSPECTION PROCEDURE 30 <EVOLUTION-IV, EVOLUTION-V>
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 Improper connector contact, open or short-circuited
harness wire
D Malfunction of engine-ECU
NG
D Check the radiator fan circuit.
D Check the A/C condenser fan circuit.
(Refer to Electrical Wirings.)
NG
Replace the engine-ECU.
OK
Check trouble symptom.
Measure at the engine-ECU connector B-59.
D Disconnect the connector, and measure at the harness side.
D Voltage between each of 20 and 21 and earth
(Ignition switch: ON)
OK: System voltage
D Short the terminal 21 to earth.
(Ignition switch: ON)
OK: Fan operates at low speed.
D Short the terminals 20 and 21 to earth.
(Ignition switch: ON)
OK: Fan operates at high speed.
OK
Check the following connector: B-59
NG
Repair
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