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 (ignition) switch (vehicles
with a smart key system)
Performing the following
operations when carrying
the electronic key on your
person starts the engine or
changes engine switch
modes.
Starting the engine
1. Check that the parking brake
is set.
2. Check that the shift lever is in
P.
3. Firmly depress the brake
pedal.
and a message will be display ...
Inspection procedure
Hint:
if dtcs p0115, p0116, p0117, p0118 and p0125 are output
simultaneously, the engine coolant temperature
sensor circuit may be open or short. Perform the troubleshooting of dtc
p0115, p0117 or
p0118 first.
Read freeze frame data using the hand-held tester or the obd ii scan
to ...
Circuit description
1 Check p squib circuit(airbag sensor assy center – instrument
panel passenger airbag assy)
Disconnect the negative (–) terminal cable from the battery,
and wait at least for 90 seconds.
disconnect the connectors between the airbag sensor
assy center and the instrument panel ...