General Precautions of EFI System Maintenance
F-59
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
Read Result I Read Result II
MIL Lamp On P-CODE Present MIL Lamp Off P-CODE Present
P0444
P0444
Maintenance tips:
The malfunction has been confirmed, and the
following problems may possibly exist
1) The circuit connected to Pin 46# of ECU and the
Pin 2# of the carbon canister control valve in
open circuit
2) The circuit for the Pin 1# of the carbon canister
control valve connected to the main relay in
open circuit
3) The electromagnetic coil between the Pin 1# and
the Pin 2# of carbon canister control valve in
open circuit
Maintenance tips:
The malfunction is not ultimately confirmed and it
may possibly be a random malfunction. Inspect the
following items:
1) Measure the electric resistance of the line
between the Pin 46# for connector of ECU and
the Pin 2# of the carbon canister control valve.
2) The electric resistance from the Pin 1# of carbon
canister control valve to the main relay
3) The electric resistance between the Pin 1# and
the Pin 2# of carbon canister control valve
74. P0458 Carbon Canister Control Valve Control Circuit Voltage too Low
Description about Malfunction Cause:
After engine has been started, the circuit voltage of the carbon canister control valve is to be measured by the
circuit control module inside ECU, and when the voltage complies with the voltage in the mode of short to
ground, it is determined to be the circuit of carbon canister control valve short to ground.
Schematic Circuit:
Main relay
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