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." property="og:description">

For Shop Owners

P0421 MAZDA - Warm Up Catalyst System Right Efficiency Below Threshold

Repair Importance Level: 2/3
Repair Difficulty Level: 2/3 What does this mean?

Possible causes

  • 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
What does this mean?

Tech notes

As the code description implies the P0421 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 code is combined with other codes, try fixing the other codes first.
What does this mean?

When is the code detected?

The P0421 code is set when the Engine Control Module (ECM) detects rear HO2S value difference becomes closer to value of front HO2S. The ECM monitors when vehicle speed is 25-60 MPH, load is 22-45 percent and engine speed is 1000-3000 RPM.

Possible symptoms

  • Engine Light ON (or Service Engine Soon Warning Light)

P0421 MAZDA 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.

OBDII Code P0421 Mazda - Warm Up Catalyst System Right Efficiency Below Threshold - itimaster.ru

Need more help?

Do you need more help with the P0421 Mazda code? Ask a question to our users or find an automotive repair shop near you to help fix the OBDII code

P0421 MAZDA Comments

Help 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
Repair Importance Level: 2
1=Low 2=Medium 3=High
Repair Difficulty Level: 2
1=Easy 2=Moderate 3=Hard

Browse All Codes For Specific Model YearBeta
Ford F150 1998 Ford F150
1999 Ford F150
2000 Ford F150
2001 Ford F150
2002 Ford F150
2003 Ford F150
Ford Fusion 2006 Ford Fusion
2007 Ford Fusion
2008 Ford Fusion
2009 Ford Fusion
2010 Ford Fusion
2011 Ford Fusion
2012 Ford Fusion
Honda Accord 2008 Honda Accord
2009 Honda Accord
2010 Honda Accord
Honda Civic 1996 Honda Civic
1997 Honda Civic
1998 Honda Civic
1999 Honda Civic
2000 Honda Civic
Infiniti G35 2003 Infiniti G35
2004 Infiniti G35
2005 Infiniti G35
2006 Infiniti G35
Nissan Altima 2002 Nissan Altima
2003 Nissan Altima
2004 Nissan Altima
2005 Nissan Altima
2006 Nissan Altima
2008 Nissan Altima
2009 Nissan Altima
2010 Nissan Altima
2011 Nissan Altima
2012 Nissan Altima
Nissan Maxima 2005 Nissan Maxima
2006 Nissan Maxima
2007 Nissan Maxima
2008 Nissan Maxima
Nissan Pathfinder 2005 Nissan Pathfinder
2006 Nissan Pathfinder
2007 Nissan Pathfinder
2008 Nissan Pathfinder
2009 Nissan Pathfinder
2010 Nissan Pathfinder
2011 Nissan Pathfinder
2012 Nissan Pathfinder
Nissan Rogue 2008 Nissan Rogue
2009 Nissan Rogue
2010 Nissan Rogue
2011 Nissan Rogue
2012 Nissan Rogue
2013 Nissan Rogue
Nissan Sentra 2002 Nissan Sentra
2003 Nissan Sentra
2004 Nissan Sentra
2005 Nissan Sentra
2006 Nissan Sentra
2007 Nissan Sentra
2008 Nissan Sentra
2009 Nissan Sentra
2010 Nissan Sentra
2011 Nissan Sentra
2012 Nissan Sentra
Toyota Camry 1997 Toyota Camry
1998 Toyota Camry
1999 Toyota Camry
2000 Toyota Camry
2001 Toyota Camry
2006 Toyota Camry
2007 Toyota Camry
2008 Toyota Camry
2009 Toyota Camry
2010 Toyota Camry
2011 Toyota Camry
Toyota Corolla 2005 Toyota Corolla
Toyota Echo 2000 Toyota Echo
2001 Toyota Echo
2002 Toyota Echo
Toyota Highlander 2001 Toyota Highlander
2002 Toyota Highlander
2003 Toyota Highlander
2004 Toyota Highlander
2005 Toyota Highlander
2006 Toyota Highlander
2007 Toyota Highlander
Toyota Prius 2004 Toyota Prius
2005 Toyota Prius
2006 Toyota Prius
2007 Toyota Prius
2008 Toyota Prius
2009 Toyota Prius
Scion xB 2005 Scion xB
2006 Scion xB
2007 Scion xB
Advertisement
Home - For Shop Owners - About itimaster.ru - Privacy Policy - Terms and Conditions - - Copyright 2010-2018 itimaster.ru
itimaster.ru - - - -
Posted and Edit by 06-14-2015

Related pages


toyota aygo owners club2003 nissan murano problemsp1492 jeep cherokee2004 mitsubishi galant recallsoutput speed sensor circuit malfunctionp1491 dodge ramobd code p0171p0174 ford f150 5.4what does code p0113 mean1999 honda civic thermostat2000 cadillac deville dhs problems2.4 ecotec engine2003 dodge neon wont start1997 chevy silverado problemscode po136infiniti fx35 transmission problemstoyota sienna vsc systemhyundai ignition coilford expedition service engine soon lightintake control solenoid valvetrouble code p1133toyota camry fuel pump2003 toyota camry intake manifoldreset check engine light hyundaiaamco fort worthecotec timing marks2006 chevy impala radiator2005 hyundai tucson electrical problemsoxygen sensor circuit high voltagep0431 mitsubishi galantstarter for 2002 mitsubishi galant2001 mercury grand marquis engine2004 dodge intrepid transmission problems2002 nissan sentra oil filterwhat is vsc light2005 dodge dakota transmission control modulemaxima cvt problemscamshaft crankshaft sensorford focus intake manifoldhonda civic 2008 transmission fluid changelexus es300 catalytic converter1998 lexus ls3002004 buick lesabre problemsvw ecmlexus maf sensorobd p0137mercury grand marquis exhaustavalon oxygenprecision tune cary nccatalytic converter efficiency codefiring order 4.2 liter fordscion xb catalytic converter2002 impala problems2003 avalanche reduced engine power2003 g35 engine2001 toyota camry engine2002 jeep liberty cylinder orderchevy uplander transmission1996 ford explorer egr valve2002 kia sportage batterynissan maxima speedometermitsubishi lancer throttle position sensoregr valve cleaning honda accorderror code 1612p0420 acura96 honda accord vtec solenoiddodge stratus check engine lightcheck engine code p01281998 ford f150 transmission slipping2104 hyundai sonatajeep patriot engine lightcode p04202004 nissan altima recallmazdaspeed rx8 intakewhat can cause a p0420 code2000 buick regal supercharged1995 honda accord exhaustcode avenger