Question about 2002 Mitsubishi Lancer

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Engine light on- PO421 Catalyst system bank 1

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Taken from: http://forums.evolutionm.net/lancer-troubleshooting/349095-code-p0421-call-mitsu-before-you-do-anything.html

Code P0421- Call Mitsu before you do anything! I called my nearest dealership today and for those who dont know, if your check engine light is on and its showing fault code P0421 this may be from a factory recall on the warm-up converter and a PCM reflash. MILEAGE OF THE CAR DOES NOT EFFECT THIS RECALL. Anyone whos had problem with a dealership not doing the repairs because of mileage needs to contact another dealer or the owner of the dealership. This is what the service manager told me today so though I'd share. Getting mine fixed tomorrow at 10am, I cant wait.

For more information about this code Google "Fault Code P0421" You'll get tons of information Last edited by Swankzer; Jun 2, 2008 at 12:31 PM.

Posted on Jan 04, 2010

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I have a 2002 dodge stratus rt and the code po421 came up when i had the emission done today and someone said that it was my catalytic converter b1 how can i find out if its bad

Posted on Jun 28, 2012

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localwonder
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SOURCE: Three trouble codes

Trouble Code: P0421


Catalyst Efficiency Below Normal (Bank 1)

Possible Causes:

Air leaks at the exhaust manifold or in the exhaust pipes
Catalytic converter is contaminated, damaged or has failed

Front HO2S and/or the rear HO2S is loose in the mounting hole

Front HO2S older (aged) than the rear HO2S (HO2S is lazy)

Front HO2S or rear HO2S is contaminated with fuel or moisture


Trouble Code: P1173

HO2S-21 (Bank 2 Sensor 1) Circuit Malfunction

Possible Causes:

Base engine mechanical fault affecting one or more cylinders

EVAP Purge valve stuck or the hoses to the valve are reversed

Fuel metering fault (fuel injector sticking open or leaking)

Fuel pressure too low or too high, fuel supply contaminated

HO2S element is contaminated or the HO2S heater has failed

PCV system has air leaks at the valve or related hoses



Trouble Code: P0174
Adaptive Fuel Trim Too Lean (Bank 2)

Possible Causes:

Vehicle driven low on fuel or until it ran out of fuel

One or more injectors restricted or pressure regulator has failed

Fuel delivery system supplying too much or too little fuel during cruise or idle periods (e.g., faulty fuel pump, or dirty fuel filter)

Air leaks after the MAF sensor, or air leaks in the PCV system

Air leaks at the EGR gasket, or at the EGR valve diaphragm

Exhaust leaks before or near where the front HO2S is mounted

HO2S is contaminated, deteriorated or it has failed

Fuel control sensor is out of calibration (i.e., ECT, IAT or MAP)

Base engine -mechanical- fault affecting one or more cylinders

Posted on May 18, 2009

  • 11 Answers

SOURCE: CHECK ENG LIGHT STILL ON

could be the knock sen-cor, map sen-cor. hope this helps.

Posted on Jan 14, 2009

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1 Answer

Po421


po421 catalytic converter code [warm up catalyst efficiency below threshold bank 1] means the o2 sensor is detecting low oxygen in exhaust problem can be cat conv going bad---o2 sensor faulty-and or bad spark plug ....as to the p0441 evap system[-evap emissions control system incorrect purge flow ] this is a system code meaning any part of the evap can have problem will need to check the fuel lines vapor lines for damage or breaks-check purge valve -purge valve solenoid- canister- and vacuum lines

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Where should i find this sensor P0342?


EXHAUST RELATED ERROR CODES

There are 711 possible PO generic DTC error codes. Only 7 of the 711 codes are exhaust related.

PO401: Insufficient EGR Flow

PO402: Exhaust Gas Recirculation (EGR) Excessive Flow Detected

PO410: Secondary Air Injection System Malfunction

PO420: Catalyst System Efficiency Below Threshold (Bank 1)

PO421: Warm-Up Catalyst Efficiency Below Threshold (Bank 1)

PO430: Catalyst System Efficiency Below Threshold (Bank 2)

PO431: Warm-Up Catalyst Efficiency Below Threshold (Bank 2)

THINGS TO ASK YOURSELF OR YOUR CUSTOMER

Have there been any driveability or performance issues with the vehicle, have there been any recent repairs or tune-up work performed, if so was the check engine light reset and were the codes recorded on previous repair orders.

Do not rely on scan tool data alone. In most applications, the customer will have the check engine light reset prior to repair. If the original cause of converter failure is intermittent, only the catalyst failure code may show up (masking the original reason for converter failure).

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What does a po430 code mean on a mercury cougar


EXHAUST RELATED ERROR CODES

There are 711 possible PO generic DTC error codes. Only 7 of the 711 codes are exhaust related.

PO401: Insufficient EGR Flow

PO402: Exhaust Gas Recirculation (EGR) Excessive Flow Detected

PO410: Secondary Air Injection System Malfunction

PO420: Catalyst System Efficiency Below Threshold (Bank 1)

PO421: Warm-Up Catalyst Efficiency Below Threshold (Bank 1)

PO430: Catalyst System Efficiency Below Threshold (Bank 2)

PO431: Warm-Up Catalyst Efficiency Below Threshold (Bank 2)

THINGS TO ASK YOURSELF OR YOUR CUSTOMER

Have there been any driveability or performance issues with the vehicle, have there been any recent repairs or tune-up work performed, if so was the check engine light reset and were the codes recorded on previous repair orders.

Do not rely on scan tool data alone. In most applications, the customer will have the check engine light reset prior to repair. If the original cause of converter failure is intermittent, only the catalyst failure code may show up

Nov 04, 2012 | Cars & Trucks

1 Answer

Code p0421 keeps coming on i erased it but it comes back on so often i dont know what too do it says that the warm up catalyst output in bank 1 is too low what does this mean please help.


CODE PO421 CATALYST EFFICIENCY BELOW NORMAL BANK 1. POSSIBLE CAUSES AIR LEAKS AT THE EXHAUST MANIFOLD OR IN THE EXHAUST PIPE.CATALYTIC CONVERTER IS CONTAMINATED DAMAGED OR HAS FAILED.FRONT HO2S AND THE REAR HO2S IS LOOSE IN THE MOUNTING HOLE. FRONT HO2S OLDER AGED THAN THE REAR HO2S IS LAZY. FRONT HO2S OR REAR HO2S IS CONTAMINATED WITH FUEL OR MOISTURE.

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What are codes P1492, P0421 & P0431 on the 2002 Mazda Millenia?


po421 warm up catalyst efficiency below threshhold bank 1, 431 same on bank 2..

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I have a 2003 MPV with trouble code PO327 and PO431. What do these mean? Thank you.


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I have a 2003 mitsubishi esclispe spyder gt


Basically this means that the oxygen sensor downstream of the catalytic converter on bank 1 is detecting that the converter is not working as efficiently as it should be (according to specs). It is part of the vehicle emissions system

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Code po421 how to fix


you have the same engine as my 2003 Galant, this should help... http://www.alldatadiy.com/alldata/AFI~V11366605~C40797~R0~OD~N/0/89012112/98644464/98644470/110938985/34853741/34857029/34857030/34857663/122915129/135964338/135975025

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CHECK ENG LIGHT STILL ON


could be the knock sen-cor, map sen-cor. hope this helps.

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2000 Mazda Miata, check engine light comes on. Code PO420


I HAVE A 2000 MAZDA MIATA AND IT IS BRINGING UP A CODE PO421, CAN YOU TELL ME WHAT THAT IS

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