Question about 2001 Mazda MPV

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Three trouble codes

First Code PO421 warm up catalyst below threshold bank 1.
Second Code P1173 no DTC definition found.
Third Code PO174 system to lean bank 2.

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  • vmoseley May 18, 2009

    Thank You for your reply. With the number of possible causes for these codes could there possibly a common cause for all of them or will each one have a different solution. If so which would be the best to start with?

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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

  • 1 more comment 
  • Michael Masters
    Michael Masters May 18, 2009

    Addressing the possible causes of each code will lead you to the exact issue and will ,also, help in fixing this situation as well.

    Please rate and have a great day:)


  • Michael Masters
    Michael Masters May 18, 2009

    Ok, each code represents an isolated issue and, each code will have to be addressed separately. All codes seem to be pointing to different sections of the engine and emissions sectors as well.

    For Example, the P0421 is mainly concerning the catalytic converter and conjoining sensors(O2). this will be mainly isolated within the exhaust system components like your exhaust manifold and gaskets and circuit O2 wiring harnesses and housings. I would start here first.


  • Michael Masters
    Michael Masters May 18, 2009

    The P0174 can be as simple as replacing the EGR valve and PCV as well but, i recommend to do a thorough inspection by using all the possible causes above so that you can cover all bases and prevent any further codes or damage.

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1 Answer

2001 chrysler sebring 3.0l lxi. what do this code po421 mean


DTC P0421: Warm up Catalyst Efficiency Bank 1 Below Threshold
  1. Sensor or solenoid faulty
  2. Connector terminal contact damaged/corroded
  3. Wire harness fault. Check for correct voltage, open, short to ground or short to voltage
  4. Control unit software needs updating
  5. PCM or ECM faulty
  6. HO2S sensor contaminated/damaged
  7. Exhaust leaks or restrictions
  8. Catalytic converter damage
  9. Catalytic converter operating incorrectly

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Car sometimes will not start after sits for a day


Definition of Diagnostic Trouble Code P0420 Category: Powertrain Definition: Catalyst System Efficiency Below Threshold Bank 1Note: This definition of P0420 is applied to all manufacturers

Definition of Diagnostic Trouble Code P0430 Category: Powertrain Definition: Catalyst System Efficiency Below Threshold Bank 2Note: This definition of P0430 is applied to all manufacturers

As the code description implies the P0430 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 P0430 code is combined with other codes, try fixing the other codes first.

Jul 11, 2015 | 2006 Toyota Solara

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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

Apr 10, 2013 | 2003 Mitsubishi Lancer

1 Answer

I've had a trouble code( P0420) code come up,


Catalyst System Efficiency Below Threshold (Bank 1). OK, now tell me that again in plain English please.... let's break it down: the catalyst system being referred to is your three-way catalytic converter; so the catalytic converter is not working properly (i.e. it's not efficient). Bank 1 refers to the side of the engine which contains cylinder #1. On inline engines such as 4 & 5 cylinder engines, there is only one bank. So, to really simply things let's just say that the efficiency of the catalytic converter and/or exhaust pipe and/or O2 sensor is not so great. Hope this helps.

Mar 09, 2013 | Cars & Trucks

1 Answer

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).

Nov 04, 2012 | Chevrolet Epica Cars & Trucks

1 Answer

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 of PO174 1 system too lean (bank 1) Code PO420 Catalyst efficiency below threshold (bank 1) Code PO430 Catalyst efficiency below threshold (bank 2)


hi,my friend, you can try,

Check for exhaust leaks at the manifold, pipes, catalytic converter. Repair as required.

Use a scope to diagnose the oxygen sensor operation (Tip: The oxygen sensor in front of the catalytic converter normally has a fluctuating waveform. The waveform of the sensor behind the converter should be more steady).

Inspect the downstream heated oxygen sensor (HO2), replace if necessary

Replace the catalytic converter

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

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NEED TO KNOW WHAT IS THI P0421 ERROR CODE


PO421:Warm Up Catalyst-below threshold (bank #1) CEL

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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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