Taking a detailed vehicle repair history with you would be an asset to you at the time of diagnosis as well. I have a Mazda 626. My car is a 2003 Audi A6 Quattro 3. This can be diagnosed by check the front and rear 02 sensors the see if they are switching at the same rate ie the cat is bad. However, an oxygen sensor is easy to replace on many cars and is usually detailed in the owner's manual. To perform the test, the computer pulls a vacuum and checks to see if the vacuum holds.
Spark plugs typically need to be replaced every season or 25 hours of use. I had one in March. When the frequency ratio of heated oxygen sensors 1 and 2 approaches a specified limit value, the three way catalyst malfunction is diagnosed. The code can be caused by any of the above listed problems. In this case, if the cam timing is over-retarded, the engine light will be illluminated and the code will be set. If the plug wires are out of sequence, the explosion occurs at the wrong time.
Thanks Bill from ohio Hi Irish, Well there are a few things that could be going wrong. Good luck Mar 25, 2010 , ckeck the upper hose to see if it is hot , than ckeck the bottom hose , is it cool , the temp sould be about the same. I checked for the code and gave me the P0421 I don't know if anyone found the answer to this but im still looking for the right answer. Physically turn the fan to see if it turns freely cold engine. Physically turn the fan to see if it turns freely cold engine.
A three way catalyst converter Manifold with high oxygen storage capacity will indicate a low switching frequency of heated oxygen sensor 2. A three way catalyst converter Manifold with high oxygen storage capacity will indicate a low switching frequency of heated oxygen sensor 2. These can range from a faulty spark plug lead, shorted kill switch or flywheel key damage. Evaporative emissions systems test for a leak in the fuel tank and associated hoses. The front cat right under the manifold might be bad. In a properly timed engine, this explosion occurs at the proper moment to send the piston to the bottom of the cylinder and provide power to the drive shaft.
The improper timing of the explosion sometimes pushes the cylinder the wrong direction or interferes with the turning of the crank. Oct 28, 2013 This code does not always mean the O2 sensor is low, but if u want to replace it here is the info to do that and the part number. If the ignition system is in poor condition or recently repaired because of misfire it could indicate that the front converter is now burnt up and requires replacement. When the frequency ratio of heated oxygen sensors 1 and 2 approaches a specified limit value, the three way catalyst malfunction is diagnosed. P0421 Mazda Possible Solution: Disconnected, dirty or fouled spark plugs are common causes for engines that won't start.
As oxygen storage capacity decreases, the heated oxygen sensor 2 switching frequency will increase. The read out states warm-up catalyst efficiency for bank 1 is below threshold. The sensor you want is the one in the exhaust pipe of the engine cylinder bank that has 1 cylinder in it, as you face the engine with the hood open the cylinder bank u want is the rear bank, u will need to jack the car up and get under it to remove the sensor, u may also need a special socket to remove it, the sensor is the one that is before the catalytic converter. So my sudgestion is to see a Mazda dealer for this code. If Rad fan not coming on when engine gets to normal operating range, either the coolant temperature sensor is faulty, or probably the relay. The counter guy suggested a tune-up.
We just took it to the dealer and they said that P0421 was the code, and the B1 and B2 warm up cats aren't working. Now don't ask yourself; What should you do with P0421 code? If the P0421 code is combined with other codes, try fixing the other codes first. If Rad fan not coming on when engine gets to normal operating range, either the coolant temperature sensor is faulty, or probably the relay. If your spark plugs look good, problems with your ignition system can also preventing a spark. Does anyone know how to solve this problem? Ive asked around and did my research and I heard i.
Need to pass ny inspection. Each car maker uses a different techniques to check, but most often it's some type of fuel tank pressure sensor. P0421 Mazda Description The Engine Control Module monitors the switching frequency ratio of heated oxygen sensors 1 front O2 sensor and heated oxygen sensors 2 rear O2 sensor. 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. Regardless of how you approach it, you should get this fixed right away.