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 description
The ecm compares the two waveforms of the heated oxygen sensors located
before and after the catalyst
to determine whether or not the catalyst performance has deteriorated.
Air–fuel ratio feedback compensation keeps the waveform of the heated oxygen
sensor in front of the catalyst
alterna ...
Terminals of ecu
1. Inspect integration relay
Disconnect the connector from the integration relay.
check the continuity between each terminal of the disconnected connector
and the body ground, as
shown in the illustration and table.
Standard:
If the result is not as specified, the vehicle’s ...
Replacement
1. Remove battery
2. Remove battery carrier
Remove the 4 bolts and battery carrier.
3. Disconnect floor shift cable transmission control shift
Remove the nut from the control shaft lever.
disconnect the control cable from the control shaft lever.
remove the clip a ...