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 ...
Replacement
1. Remove clutch start switch assy
disconnect the clutch start switch assy connector.
remove the nut and clutch start switch assy from the clutch pedal
support.
2. Install clutch start switch assy
install the clutch start switch assy with the nut.
Torque: 15.68 Nv ...
Overhaul
1. Remove speedometer drive (mtm) gear
Remove the speedometer drive (mtm) gear from the front
differential case.
2. Remove front differential ring gear
Place matchmarks on the front differential ring gear and
front differential case.
Remove the 8 bolts. Using a hamme ...