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
1. Intake air flow meter sub–assy
Inspect the intake air flow meter resistance.
Using an ohmmeter, measure the resistance between
terminals tha and e2.
Resistance:
at –20 c (–4 f) 13.6 To 18.4 KΩ
at 20 c (68 f) 2.21 To 2.69 KΩ
at 60 c (140 f) 0.49 To 0.67 ...
Road test
1. Problem symptom confirmation
Taking into consideration the results of the customer problem analysis,
try to reproduce the symptoms
of the trouble. If the problem is that the transaxle does not shift up,
shift down, or the shift point is too
high or too low conduct the following road ...
Replacement
1. Work for preventing gasoline from spilling out
2. Remove engine under cover rh
3. Drain coolant
4. Remove front wheel rh
5. Remove cylinder head cover no.2
Remove the 2 nuts, 2 clips and cylinder head cover.
6. Remove air cleaner hose no.1
loosen the 2 air cleaner hose ...