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:
Thermostat
Replacement
1. Remove engine under cover rh
2. Drain coolant
3. Remove fan and generator v belt
4. Remove generator assy
Disconnect the wire clamp from the wire clip on the rectifire
end frame.
remove the rubber cap and nut, and disconnect the alternator
wire.
d ...
Inspection procedure
1 Check relay (marking: starter cut)
Inspect the relay continuity, as shown in the illustration
and table.
Standard:
2 Check tvip ecu
Disconnect the tvip ecu connector.
turn the ignition switch position to the start.
measure the voltage between the termina ...
How to proceed with troubleshooting
Troubleshoot in accordance with the procedure on the following pages.
1 Vehicle brought to workshop
2 Customer problem analysis check and symptom check
Without applicable symptoms, proceed to ”a”.
with applicable symptoms, proceed to ”b”.
3 Symptom simulation
4 Prob ...