Toyota Corolla Repair Manual: Catalyst system efficiency below threshold
Dtc p0420 catalyst system efficiency below threshold (bank 1)
Inspection procedure
Hint:
read freeze frame data using the hand-held tester or the obd ii scan tool.
Freeze frame data records the
engine conditions when a malfunction is detected. When troubleshooting, it is
usefu ...
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 feedba ...
Other materials:
Overhaul
1. Remove console panel upper
2. Remove console box carpet
3. Remove parking brake hole cover sub–assy
4. Remove console box sub–assy rear
5. Disconnect floor shift cable transmission control shift
Remove the cable end from the rod of the floor shift assembly.
Using a screw ...
Confirmation driving pattern
Connect the hand–held tester or the obd ii scan tool to the dlc3.
record dtcs and the freeze frame data.
set the check mode using the hand–held tester .
read the value on the misfire counter for each cylinder when
idling. If the value is displayed on the
misfire count ...
Other functions
■ Switching between outside air and recirculated air modes
Press .
The mode switches between outside air mode (indicator off) and recirculated air
mode (indicator on) each time is pressed.
■ Defogging the windshield
Defoggers are used to defog the windshield and front side windows ...