Mazda mpv 2003 check engene light code p0421 warm up catalist ...

code p 0421 refers to warm up cat converter bank 1--efficiency below threshold ===causes ---cat converter---wiring---HO2S 2
( heated oxygen sensor)
code p 0431 refers to warm up cat conveter bank 2--efficiency below threshold === causes cat converter --- wiring---HO2S 2
as the same HO2S appears in the cause of the fault I would be inclined to change it first
the HO2sS sensor is the one in the exhaust manifold or before the cat converter
and 2 is in the front bank of a V engine
use the special socket when removing/ replacing these sensors as an incorrect tool is the main reason for wire failures on the sensors

Error Code: P0421
Description:
Warm Up Catalytic Converter, Bank 1 - Efficiency Below Threshold
Possible Cause:
Warm Up Catalyst Bank 1 faulty.
Possible Solutions:
Check Warm Up Catalyst Bank 1 - Set Readiness.
Replace Warm Up Catalyst Bank 1.

P0421 Warm Up Catalyst Efficiency Below Threshold (Bank 1)
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Can Clip Renault

the temperature cooling sensor, The sensor's output is monitored by the engine computer to regulate various ignition, fuel and emission control functions, and to turn the radiator-cooling fan on and off as needed. check this first ! also check the fan relay in relay box. it may be sticking in the on position. hard to say without being there. but try the above things. good-day ! the fans come on if a/c is on.

catylitic converter has issues--if your state has inspections then get it tested

code P0421 may mean that one or more of the following has happened:

• The catalytic converter is no longer functioning properly
• An oxygen sensor is not reading (functioning) properly
• A sparkplug is fouled up

Possible Solutions

could anyone please help me with this problem that i have with my 2001 mazda protege es 2.0. i have a bad catalyst converter and im waiting for the converter to come in, but before the guys that are fixing on my car relize that i need a converter they put a egr valve and a o2 senor and when the car idle some time it will just die one me. could someone tell me what is going on.

did you check your transmission fluid

all these codes can be problem except 306 misfire start with 103 113 and 335

If you need further help, reach me via phone at https://www.6ya.com/expert/james_9c1b039055413ffa

P0031 - most likely pointing to a failed O2 sensor (bank 1 sensor 1 is located before the catalytic converter)

P0421 - failed catalytic converter or a failed O2 sensor

P1512 - intake manifold shutter valve is stuck - may be caused by the O2 sensor, but may not

I recommend replacing your O2 sensor first and see what happens