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:
Inspection procedure
1 Input signal check
See the input signal check on page 05–745.
check the indicator light when the clutch pedal is depressed.
Ok:
the indicator light goes off when the clutch pedal is
depressed.
2 Inspect terminal voltage(d)
Turn the ignition switch to on.
&n ...
Overhaul
Hint: components:
1. Discharge refrigerant from refrigeration system
sst 07110–58060 (07117–58080, 07117–58090, 07117–78050, 07117–88060,
07117–88070,
07117–88080)
2. Disconnect cooler refrigerant liquid pipe a
Remove the bolt and disconnect the cooler refrigerant liqui ...
Emission inspection and maintenance (I/M) programs
Some states have vehicle emission inspection programs which include OBD (On
Board Diagnostics) checks. The OBD system monitors the operation of the emission
control system.
If the malfunction indicator lamp comes on
The OBD system determines that a problem exists somewhere in the emission cont ...