Taking a detailed vehicle repair history with you would be an asset to you at the time of diagnosis as well. Not sure if this is what's wrong with your, but suggest you chek the simply stuff first. 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. I have a California Emissions type cat in my vehical so that makes replacement most expenisice. Anyone whos had problemwith a dealership not doing the repairs because of mileage needs tocontact another dealer or the owner of the dealership. Also check for bad fuel injectors.
The code refers to Warm up Catalytic Converter below threshold Bank 1 which means the two oxygen sensors before and after the cat closest to the engine are showing a variance that is outside specifications. I found those sites to be useful that I found with the Google search. Autozone checked and code P0421 came on. Thanks for the comments and suggestions. Before continuing, try to get some clarification from the guy on this point. In most areas if it is on, the car will automatically fail emissions.
I have a Mazda 626. The two catalyst system is common to some cars. One for the front bank or front three cyl, and one for the rear bank or rear three cyl. If your are for a different car, select that vehicle series before searching for the diagnostic codes because not all used by one manufacture are used by the other makes. The read out states warm-up catalyst efficiency for bank 1 is below threshold.
Probable faults and reasons: Igniter no. I heard on another forum the cats and maybe the O2 sensors are covered under 8 year emission warranty. Many times when they throw a code, it's the sensors themselves that have a problem. This is what the service manager told me today so though I'd share. Everything was fine until about a month went past and the error code came back. Spark plug is short or its air too wide.
What does that mean and where do I go from here? The O2 sensors are the only data that anyone uses today unless the drag out the emissions sensor dino from the closet. If the light stays off for 2 days, go get your emissions test. Mechanic 3 that I spoke with today was the one the only one that said that my car had 2 catalitic converters. I found out a little more. Generally, this code can be caused by the following: 1 Catalytic converter defective 2 Engine Misfire or similar 3 Large vacuum leak 4 Engine oil leakage into exhaust -valve guide seals, piston rings I have learned to always look for the simplest solution before paying big bucks for things like catalytic converters, oxygen sensors, etc. You said in a previous post it was a 4-cylinder car…If so, there will only be 2 oxygen sensors, front and rear.
You add the product into fuel tank before you fill up. Also check wiring as these sensors are low to the ground. I had one in March. For item 3, try moving the Bank 1 sensor to Bank 2 and see if the fault also moves -- if it does, then the aft bank 1 sensor is defective. Getting mine fixed tomorrow at 10am, I cant wait.
I am in Canada, here Mazda has a 3 year 80k warrenty on bumper to bumper warrenty, thern a 5 year 100km on their powertrain. The counter guy suggested a tune-up. You could also have leaking fuel injectors that are ok when the engine is hot but throw a code when the engine and the converter is cold. They may have already found the solution. This is what theservice manager told me today so though I'd share.
Took off the heat shield and could see the black residue from exhaust escaping the crack. Engine valves and seats defective. I think you probably need a new one. The P0421 code is set if the quotent of the frequency of the rear O2 sensor divided by the frequency of the front O2 sensor is above 0. It may take a couple of treatments to do the job.