Toyota 1 MZ–FE Manual page 557

DTC P1500 Starter Signal Circuit Malfunction
CIRCUIT DESCRIPTION
When the engine is cranked, the intake air flow is slow, so fuel vaporization is poor. A rich mixture is
therefore necessary in order to achieve good startability. While the engine is being cranked, the battery
voltage is applied to terminal STA of the ECM. The starter signal is mainly used to increase the fuel injec-
tion volume for the starting injection control and after–start injection control.
Diagnostic Trouble Code Detecting Condition
DTC No.
P1500
No starter signal to ECM.
HINT: In this circuit, diagnosis can only be made in the check mode.
DIAGNOSTIC CHART
HINT: This diagnostic chart is based on the premise that the engine is cranked normally. If the engine is
not cranked, proceed to the matrix chart of problem symptoms on page EG2–435.
Connect the TOYOTA hand–held tester and check
STA signal.
Check for open in harness and connector between
ECM and starter relay.
Check and replace ECM.
WIRING DIAGRAM
1MZ–FE ENGINE – CIRCUIT INSPECTION
Open or short in starter signal circuit.
Open or short in ignition switch or starter relay
circuit.
ECM
Trouble Area
Proceed to next circuit inspection shown
on matrix chart.
Repair or replace harness or connector.
EG2–557