#FORD ENGINE CODES P430 HOW TO#
#FORD ENGINE CODES P430 CODE#

If it does toggle between rich and lean, the sweep should be fairly mild. If the catalytic converter is doing its job properly, the downstream O2 sensor, located AFTER the cat converter, should rarely switch between rich and lean. If thereвЂ™s too much oxygen left over after combustion, the catalytic converter stores that oxygen to use to help burn off the next round of excess fuel. If the PCM overshoots and provides too much fuel, that extra fuel gets burned off in the catalytic converter. Since the PCM is constantly playing вЂњcatch-upвЂќ to recalculate. In other words, the PCM is constantly overshooting and undershooting the air/fuel mixture and trying to narrow the gap between the two. That sounds easy, right? BUT, since youвЂ™re constantly changing what youвЂ™re asking from the engine by going up and down hills, accelerating and decelerating, the computer is CONSTANTLY recalculating the air/fuel mixture and the upstream O2 sensor is CONSTANTLY reporting how well the PCM did. If the reading is too lean, itвЂ™ll add fuel. If the readings shows the exhaust is rich, the PCM will cut back on fuel. To check on how well it did calculating the air/fuel mixture, it checks the readings from upstream oxygen sensors (O2). Then it calculates how much fuel is required to get you the power you need AND complete burn so you donвЂ™t pollute the air.

At that point the PCM knows air temp, engine temp, air density and how much power youвЂ™re asking for. The powertrain control module (PCM) receives inputs from the engine coolant temp sensor (ECT), the mass airflow sensor (MAF), and the throttle position sensor (TPS). How the air and fuel mixtures are calculated But first you have to understand how the air/fuel and emissions systems work. After the tests you may indeed discover that the catalytic converter is bad.

#FORD ENGINE CODES P430 CODE#

When attach a trouble code reader and come up with a P0420, your first assumption may be that you need a new catalytic converter, simply because the words catalytic converter are mentioned in the code.

#FORD ENGINE CODES P430 HOW TO#

Repair Topics > Computers and Sensors > How to fix Code P0420 How to fix Code P0420 What is code P0420 Catalyst System Efficiency Below Threshold

Ford engine codes p430