Toyota 3VZ–FE Troubleshooting Manual page 163

EG–162
ELECTRONIC CONTROL SYSTEM
The control system consists of sensors which detect various engine conditions, and a ECM which deter-
mines the injection volume (timing) based on the signals from the sensors.
The various sensors detect the intake air volume, engine rpm, oxygen density in the exhaust gas, engine
coolant temperature, intake air temperature and atmospheric pressure etc. and convert the information into
an electrical signal which is sent to the ECM. Based on these signals, the ECM calculates the optimum
ignition timing for the current conditions and operates the injectors.
The ECM not only controls the fuel injection timing, but also the self diagnostic function which records the
occurrence of a malfunction, ignition timing control, idle rpm control, fuel pressure control and fuel pump
control.
ENGINE TROUBLESHOOTING – SFI SYSTEM
EG0FY–02