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:
Replacement
1. Drain engine oil
remove the oil pan drain plug and drain the engine oil.
2. Removal & installation chain sub–assy
3. Remove chain vibration damper no.1
remove 2 bolts and chain vibration damper no. 1.
4. Remove oil pump assy
Remove the 5 bolts.
rem ...
Inspection
1. Cooler thermistor no.1
Check resistance between terminals 1 and 2 of cooler
thermistor no. 1 At each temperature, as shown in the
chart.
Resistance:
If resistance value is not as specified, replace the sensor.
2. Cooler and accessory assy
Inspect blower switch contin ...
Inspection procedure
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 ...