When the frequency ratio of heated oxygen sensors 1 and 2 approaches a specified limit value, the three way catalyst malfunction is diagnosed. In this case, if the cam timing is over-retarded, the engine light will be illluminated and the code will be set. What are the causes of the P0421 code? When you fill your car with gas, the vapors in the tank get forced into a canister filled with activated charcoal. If the catalytic converter has failed and the engine is not running properly, severe engine damage can result from continuing to drive the vehicle. Spark Plugs If your Equus has fouled or is fouling plugs, it may be most apparent at start up.
This code means that the computer is detecting the catalyst not warming up to full function quickly enough based on information from the post cat O2 sensor. P0421: Warm up catalyst efficiency below threshold. Closed throttle position switch is off. Typically the P0420 code triggers the Check Engine Light if the readings of the two sensors are similar. If the P0421 code is combined with other codes, try fixing the other codes first.
You should also check that the spark plug gap is set properly. P1818 - Manufacturer specific code. Hi jorge10928, After checking through again, I realised I made a mistake regarding the catalytic converter. Will I need to replace the front cat? If problem does not exist, go to next step. You could have a catalaytic converter that is inefficient or the O2 sensors are not functioning as required. YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle.
After this brief flash, the light should stay off while you drive as long as no problems are detected. At some point it has to be emptied. The radio code for each Hyundai vehicle is unique. You will likely not notice any drivability problems, although there may be symptoms. Other ignition related components can cause the code as well such as plug wires, coils, etc…. If you don't have this card you will need to take your vehicle to your Hyundai dealer where they will remove the radio, obtail the serial number then contact Hyundai to find out what your code is :.
You should do the diagnostic as per procedures above to verify before doing any replacement. A three way catalyst converter Manifold with high oxygen storage capacity will indicate a low switching frequency of heated oxygen sensor 2. 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. It is used only for on board diagnosis. The scanner says it has two codes but they are both P0421.
Fuel pump pressure too high. The catalyst causes the rear oxygen sensor to have a lower frequency. How serious is the P0421 code? If the engine is a 4 cly I4 , there is only one bank and is designated Bank 1 exhaust manifold. In order for an engine to run well, it must be able to breathe properly. The Powertrain Control Module compares the output signals of the front and rear oxygen sensors to determine whether the output of the rear sensor is beginning to match the output of the front oxygen sensor. Spark plug is short or its air too wide. Once the engine and plugs warm up its business as usual.
As oxygen storage capacity decreases, the heated oxygen sensor 2 switching frequency will increase. If the visual test checks out, the mechanic may then move on to testing the oxygen sensors and the powertrain control module starting with the sensors. A completely worn catalyst shows a 100% match between the frequency of the front and rear sensors. If no leak is found, go to next step. But the charcoal can only hold so much vapor. .
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. 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. In fact, if you find this code with no other codes, it is highly likely the Cat or the exhaust system in general is the problem. Hi jorge10928, The price I got is from my estimator courtesy of but the actual price have to be enquired at the dealer as these prices are sometimes not up to date. A bad O2 sensor is one of the most common cause of this code.
Tech notes As the code description implies the P0421 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. The catalyst causes the rear oxygen sensor to have a lower frequency. Also, on a hot day as the gas heats up and vaporizes, those same vapors push into the canister where they're stored. It should be joined from the front of exhaust manifold to the rear exhaust system. These can range from a faulty spark plug lead, shorted kill switch or flywheel key damage. And I was told my car had 2 converters. O2 Sensors If the Oxygen sensors are no longer reading properly, it can throw the P0421 code.
P0421 Hyundai Possible Solution: Disconnected, dirty or fouled spark plugs are common causes for engines that won't start. In fact, it would be a good idea to test each oxygen O2 sensor while you're at it. You'll be glad to know that your vehicle is equipped with an early warning system that could save you time, money, and fuel in addition to helping protect the car! Inspect for exhaust leaks upstream and downstream of catalytic converter. If the P0421 code was the only code stored in the system, the mechanic may begin diagnosing this issue by taking a look at the exhaust system. Once you do this and let us know what, if any codes are set, then we can go from there. I had provided you with info for a V6 engine. Catalyst System Efficiency Below Threshold Bank 1 The catalytic converter has an oxygen sensor in front and behind it.