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:
Check open circuit
For the open circuit in the wire harness in fig. 1, Perform
a resistance check in step (b) or a voltage check in step
(c) to locate the section.
Check the resistance.
Disconnect connectors a and c and measure the
resistance between them.
Resistance: 1 Ω or les ...
Windshield wiper switch assy
Replacement
1. Remove steering column cover lwr
Remove 3 screws and steering column cover lwr.
2. Remove windshield wiper switch assy
Disconnect the connecter of the windshield wiper switch.
release the claw and pull out the windshield wiper switch
assy as shown in the ...
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
useful for determining whether
the vehicle was running or stopped, the engine was warmed up or not, the ...