Toyota 1 MZ–FE Manual page 550

EG2–550
DTC P1300 Igniter Circuit Malfunction
CIRCUIT DESCRIPTION
The ECM determines the ignition timing, turns on Tr1 at a predetermined angle ("CA) before the desired
ignition timing and outputs an ignition signal (IGT) "1" to the igniter.
Since the width of the IGT signal is constant, the dwell angle control circuit in the igniter determines the
time the control circuit starts primary current flow to the ignition coil based on the engine rpm and ignition
timing one revolution ago, that is, the time the Tr2 turns on.
When it reaches the ignition timing, the ECM turns Tr1 off and outputs the IGT signal "0".
This turns Tr2 off, interrupting the primary current flow and generating a high voltage in the secondary coil
which causes the spark plug to spark. Also, by the counter electromotive force generated when the primary
current is interrupted, the igniter sends an ignition confirmation signal (IGF) to the ECM.
The ECM stops. fuel injection as a fail safe function when the IGF signal is not input to the ECM.
Diagnostic Trouble Code Detecting Condition
DTC No.
No IGF signal to ECM for 6 consecutive IGT
P1300
signals during engine running.
WIRING DIAGRAM
1MZ–FE ENGINE – CIRCUIT INSPECTION
Open or short in IGF or IGT circuit from igniter
to ECM.
Igniter
ECM
Trouble Area