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:
Circuit inspection
1 Check d squib circuit(airbag sensor assy center – horn button
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 horn button assy.
connect the ...
Inspection procedure
Hint:
troubleshoot each trouble symptom in accordance with the chart below.
1 Clear dtc
Connect the hand–held tester or the obd ii scan tool to the dlc 3.
turn the ignition switch on and push the hand–held tester or the
obd ii scan tool main switch on.
read the dtc . ...
On–vehicle inspection
1. Connect hand–held tester:
connect the hand–held tester to the dlc3.
start the engine and run it at idle.
select the active test mode on the hand–held tester.
Hint:
please refer to the hand–held tester operator’s manual for further details.
2. Inspect actua ...