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:
Wiper & washer
Preparation
Sst
Recomended tools
Equipment
...
Transmitter battery
Replacement
1. Replace transmitter battery
Notice:
special caution should be taken for handling each component as they are
precision electronic components.
Using a screwdriver, pry out the transmitter case.
Notice:
do not forcibly pry out the case.
Hint:
tape the screwdriver tip ...
Inspection procedure
1 Check courtesy lamp switch
Check the courtesy switch, as shown in the illustration
and table.
Standard:
2 Check wire harness (integration relay door courtesy sw)
Disconnect the integration relay and door courtesy connectors.
check the continuity between th ...