General Precautions of EFI System Maintenance
F-74
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
SVS lamp On P-CODE Present SVS lamp Off P-CODE Present
P0646 P0646
Maintenance tips:
The malfunction has been confirmed, and the
following problems may possibly exist
1) The circuit connected to Pin 69# of ECU short
to ground
Maintenance tips:
The malfunction is not ultimately confirmed and it
may possibly be a random malfunction. Inspect the
following items:
1) Whether or not the resistance for Pin 69# of
ECU to Ground is under normal condition
94. P0647 Control Circuit of A/C Compressor Relay Short to Power Supply
Description about Malfunction Cause:
After engine has been started, the voltage of relay circuit is to be measured by circuit control module inside
ECU, and when the voltage complies with the voltage in the mode of short to power supply, it is determined to
be the malfunction of short to power supply.
Schematic Circuit:
Battery
Main relay
A/C Compressor Relay
To Next Page
