General Precautions of EFI System Maintenance
F-62
Malfunction Diagnostic Guide:
Required Equipment: (Diagnostic Instrument with EOBD Diagnostic Function, Digital Multimeter, and
Correct Circuit Diagram)
Step I: Use diagnostic instrument to read the malfunction information
Maintenance tips:
The malfunction has been confirmed, and the
following problems may possibly exist
1) Open circuit between ECU Pin 50# and cooling
fan relay Pin 85
2) Open circuit between cooling fan relay Pin 86#
and main relay
3) Open circuit between cooling fan relay Pin 30#
and battery
Maintenance tips:
The malfunction is not ultimately confirmed and it
may possibly be a random malfunction. Inspect the
following items:
1) Examine resistance of circuit between Pin 50# of
ECU connector and Pin 85# or cooling fan relay
2) Resistance of circuit between cooling fan relay
Pin 86# and main relay
3) Resistance of circuit between cooling fan relay
Pin 30# and battery
77. P0481 Control Circuit of Cooling Fan Relay is Open (High Speed)
Description about Malfunction Cause:
After engine has been started, circuit control module of ECU examines voltage of cooling fan circuit. If open
circuit mode value is detected, malfunction of open cooling fan circuit is indicated.
Schematic Circuit:
Battery
Main relay
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