Enter the 5 character trouble codes in the search box and submit the search. The emissions system has two cats and two O2 sensors. You mentioned you had one replaced. I've even wondered if it's a computer issue. The connector may have a removable cover.
It is tricky to find however. If the upstream and downstream O2 sensors reflect a similar exhaust oxygen concentration, a code P0421 will be stored and a malfunction indicator lamp may be illuminated. If you have over a 100k on your car, replace it. Don't have one get one. To find you, you need to analyze the situation.
I get the impression it is the cat. In most cases fixing the problem makes the light go out. The mechanic may do multiple things to check the condition of the catalytic converters, such as smelling the fumes from the exhaust to check for excessive fuel, checking the catalytic converters with the engine running to see if they turn red, and also doing a road test of the vehicle to confirm the customers symptoms. I stop at autoparts store and get a misfire code P0300 and P0421. If either sensor isn't working correctly, the car will run rough and the engine will be less efficient. You can replace the parts because they lose efficiency from age and use, but it really doesn't always cure the problem. I don't have the car anymore.
Also my mileage has remained the same. We do our best to update these Mazda check engine light codes as frequently as possible. Are there any aftermarket options that are cheaper? This holds especially true when considering that the catalytic converters are usually the most expensive part of the whole exhaust system. Intermittent codes can be much harder to diagnose. A three way catalyst converter Manifold with high oxygen storage capacity will indicate a low switching frequency of heated oxygen sensor 2. It is part of the vehicle emissions system. You can also temporarily bypass the heater core until you can get it fixed.
Thanks for the response Chapper. You will notice a decrease in gas mileage and over time the car will eventually start stalling a lot. If in doubt replace the cam angle sensor. And lets face it, if the service engine light is on then you need it now! If the catalytic converter has failed and the engine is not running properly, severe engine damage can result from continuing to drive the vehicle. Remember, these are manufacturer specific codes only.
But one of the main causes of cat codes is bad tune up or engine miss or running rich. A diagnostic scanner, digital volt ohmmeter , and a reliable vehicle information source such as will prove necessary when diagnosing a code P0421. Fluctuations in voltage occur as the surging oxygen ions bounce between platinum layers. When the signal output from the O2 sensor is lower, more oxygen is present in the exhaust lean condition. If it gets out of this range it will set the code Not necessarily.
In later car models, the car's computer can usually keep the vehicle running, but the engine warning light on the dashboard goes on to warn the driver. Deviations between the concentration of oxygen molecules in ambient air drawn into the O2 sensor and the concentration of oxygen ions in the exhaust cause voltage fluctuations. If a catalytic converter has melted internal parts, or has been clogged up by carbon deposits, the engine will not be able to breathe properly and will therefore run poorly. If the engine won't crank, you… I assume you mean the rotor for the distributor. Circuit P1686 Metering Oil Pump Stepping Motor Cont. Need help with a P0421 code? She didn't hit very hard- mostly scs along the quarter panel.
With a P0421, I would begin with a visual inspection of system wiring harnesses and connectors. Use caution and disconnect related controllers before attempting to test system circuit resistance with the. I have a 99 10ae with the same issues and I'm trying to decide if it's worth putting anymore money in to it. Also sometimes there is a pcm reflash for the pro. I have replaced the 2nd coil since my last post. You will need to follow the lower radiator pipe back to the engine and you will find the flexy pipe will be clamped to a metal pipe.
Consider this a maintenance item. P0421 Code Definition Warm Up Catalyst Efficiency Below Threshold Bank 1 What the P0421 code means The P0421 code means that the powertrain control module is noticing that the catalyst system is not performing as it should during warm up conditions. An aftermarket header would be an option too, again with O2 relocations. The method above is specifically for making everything look kosher for strict inspection, as done in California. It is constructed using a filtration element of ceramic and precious metals enclosed in a steel housing and placed in the exhaust pipe. It depends on what you mean by a bad heater core. So you should chech it on our car models.