P0420 Volvo Catalyst System Efficiency Below Threshold Bank 1

P0420 Volvo Catalyst System Efficiency Below Threshold Bank 1

Possible causes
– Three way catalyst converter 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)
Tech description
As the code description implies the P0421 Volvo code means that the vehicle’s control module has detected that the three-way catalytic converter is not working properly (is not as efficient as the factory is expecting). Replacing the oxygen (O2) sensors may sometimes fix the code, but in most cases the catalytic convert needs to be replaced to fix the problem. If the P0421 Volvo code is combined with other codes, try fixing the other codes first.
What about the obd code?
– Three way catalytic converter Bank 1 does not operate properly.
– Three way catalyst converter Bank 1 does not have enough oxygen storage capacity.
Symptoms
– Engine Light ON (or Service Engine Soon Warning Light)
P0420 Volvo Description

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.

Volvo Vehicle:Volvo C70,Volvo S40,Volvo XC90,Volvo XC70,Volvo XC60,Volvo V70,Volvo V50,Volvo V40,Volvo S90,Volvo S80,Volvo S60
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