Toyota COMPUTER-CONTROLLED SYSTEM

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DIAGNOSIS - "CHECK ENGINE" Lamp and VF or VF1 Terminal Outpu t
ENGINE ECU DATA OUTPUT ( TE2 terminal on )
In engines having a test mode for diagnosis, the
Engine ECU has the function to output data
calculated according to signals from each sensor .
Output data accounts for a portion of input data
from sensors and output data to actuators . Since
the data is output in the form of serial communica-
tions, it cannot be read without using a TOYOTA
hand-held tester, DIAGNOSIS READER or
DIAGNOSIS MONITOR .
Refer to the Repair Manual or the Handling
Manual of a TOYOTA hand-held tester,
DIAGNOSIS READER or DIAGNOSIS MONITOR
for information on the reading procedure and out-
put parameters .
~ REFERENCE
I Serial Communication :
Serial communication is one of digital com-
munication . One piece of data is sent by com-
bining high (1) and low (0) signals for each unit
time (t) .
Multiple pieces of data can be sent with a
single communication line .
Hig h
Low J
t' t2 t3 /