Toyota Corolla (E120) 2002–2008 Repair Manual / Diagnostics / Sfi system / Catalyst system efficiency below
threshold
Toyota Corolla (E120): Catalyst system efficiency below threshold
Dtc p0420 catalyst system efficiency below threshold (bank 1)
Other materials:
Engine immobilizer system
The vehicle’s keys have built-in transponder chips that prevent the engine
from starting if a key has not been previously registered in the vehicle’s on-board
computer.
Never leave the keys inside the vehicle when you leave the vehicle.
Vehicles without a smart key system: The indicator li ...
Brake
Preparation
Sst
Recomended tools
Equipment
Lubricant
...
Circuit description
When the ignition switch is turned on, battery positive voltage is applied to
the coilwhich closes the contacts
of the efi main relay (marked: efi) and supplies power to terminal +b of the ecm.
This signal causes current to flow to the coil, closing the contacts of the efi
relay and supplyin ...