Description of On-Board Diagnostics
DIAGNOSIS SYSTEM DESCRIPTIONThe engine ECU contains a built-in, self-diagnosis system which detects troubles within the engine signal network and flashes the "CHECK ENGINE" warning light in the combination meter.
By analyzing various signals as shown in the later tables, the Electronic Control Unit (ECU) detects system malfunctions which are related to the various operating parameter sensors or to the actuator. The ECU stores the failure until the diagnosis system is cleared by removing the EFI fuse with the ignition switch off.
A "CHECK ENGINE" warning light in the combination meter informs the driver that a malfunction has been detected. The light goes off automatically when the malfunction has been cleared.
"CHECK ENGINE" WARNING LIGHT CHECK
1. The "CHECK ENGINE" warning light will come on when the ignition switch is placed at ON and the engine is not running.
2. When the engine is started, the "CHECK ENGINE" warning light should go off.
If the light remains on, the diagnosis system has detected a malfunction or abnormality in the system.
NOTE: Toyota does not provide trouble code driven diagnostic procedures for this vehicle. For information regarding diagnostic procedures, see "Non-Trouble Code Diagnostic Procedures/Troubleshooting with Volt/Ohm Meter." Troubleshooting With Volt/Ohmmeter