P0421 MAZDA - Warm Up Catalyst System Right Efficiency Below Threshold
- Warm Up Three Way Catalytic converter deterioration or malfunction
- Exhaust system leaks
- Loose front or rear HO2Ss
- Faulty front heater O2 sensor
- O2 sensors harness is open or shorted
- O2 sensors poor electrical connection
When is the code detected?
- Engine Light ON (or Service Engine Soon Warning Light)
P0421 MAZDA Description
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.
Need more help?
P0421 MAZDA CommentsHelp us improve itimaster.ru. Leave a comment below or tell us if the information above help you fix the code. What are the symptoms on your vehicle for the P0421 Mazda code? Have you replaced any parts?
Any information is appreciated. Thanks