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:
For vehicles equipped with catalytic converter
Caution:
if large amount of unburned fuel flows into the converter, it may cause
overheating and a fire hazard.
To prevent this, observe the following precautions.
Use only unleaded gasoline.
avoid prolonged idling.
Avoid running the engine at idle speed for more than 20 minutes. ...
Problem symptoms table
The suspected circuits or parts for each problem symptom are shown in the
table below. Use this table to
troubleshoot the problem when a normal code is displayed in the diagnostic
trouble code chart but the problem
is still occurring. Numbers in the table indicate the order in which the
circ ...
Communication system
Horn system
Location
Problem symptoms table
Inspection
1. Inspect low pitched horn assy
Connect the positive (+) lead from the battery to the terminal
and the negative (–) lead to the horn body, and check
that the horn blows.
If the result is not as specified, replace the ...