P0420 HONDA - Catalyst System Efficiency Below Threshold Bank 1
- Exhaust tube
- Intake air leaks
- Fuel injectors may be faulty
- Fuel injector leaks
- Spark plugs may be faulty
- Improper ignition timing
- Engine Control Module (ECM)
- Three way catalyst converter Bank 1 does not have enough oxygen storage capacity.
The Engine Control Module (ECM) monitors the switching frequency ratio of heated oxygen sensors 1 (front O2 sensor) and heated oxygen sensors 2 (rear O2 sensor).
A three way catalyst converter (Manifold) with high oxygen storage capacity will indicate a low switching frequency of heated oxygen sensor 2. As oxygen storage capacity decreases, the heated oxygen sensor 2 switching frequency will increase.
When the frequency ratio of heated oxygen sensors 1 and 2 approaches a specified limit value, the three way catalyst malfunction is diagnosed.
P0420 1997 HONDA CIVIC
P0420 1998 HONDA CIVIC
P0420 1999 HONDA CIVIC
P0420 2000 HONDA CIVIC
the car would not pass smog because the computer would reset it self so we did some researdh and fou...
Reset ECM to erase Code P0420, engine light came back on after driving 75 miles and stayed on. What ...
ok my problem is this p0420 code came on I changed the cat conv and the 2 oxygen sensor now its comi...
Is it serious....i got my car scaned and the check engine light still on because of the p0420....Wil...
Any information is appreciated. Thanks