P0420 LEXUS - 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.
my diagnostic reading said PO456, the emission system leak is very small, could this be why I also h...
Hi, Got a used car Lexus GX460 delivered to me and immediately checked it out and got the following...
P0430 AND P0420 Lexus -2005 330 RX...
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Any information is appreciated. Thanks