Since 1996 modern vehicles have used an on-board diagnostic system (aka OBD) that frequently causes the dreaded check engine light to come on An OBD-II scanner (as they are known nowadays) throw out codes we see in the shop on a daily basis. Let’s look at some of the most frequently seen codes. read on to learn more.
Cylinder Misfire (P0300)
This code means the vehicle combustion is not working properly in one or more of the cylinders in the engine. You will see, hear and feel the engine running roughly or being abnormally loud when idling. it may also cause power to be lost. This should be seen as a symptom of something rather than a specific issue as its cause can vary. From sensors that have gone bad, to components that have worn out, issues with emission or vacuum leaks. On occasion the code appears with a different number other than zero at the end. For example when it ends in 3, it refers to the third engine cylinder.
Evaporative Emission System Leak (P0440, P0455, P0442)
These codes appear to report a leak the evaporative emission system. Remember, gasoline is both a liquid and a vapor. Now, vehicles have a system to prevent fumes from escaping places like fuel lines and tanks. If the tank pressure drops, the code can kick-in. Other ways this code may be triggered include a missing or loose gas cap, a charcoal canister that has become damaged or the filler neck has developed a leak. There may also be an odor of gas.
Catalytic Converter Inefficiency (P0420, P0430)
There are various things that could cause the P0420 and P0430 codes to show up, but the most typical one is a broken catalytic converter. These errors can also be caused by a malfunctioning oxygen sensor, an engine that is running too rich or too lean, or a leak in the exhaust system.
Evaporative Emission System Incorrect Purge Flow (P0411)
Unfortunately, this can happen when the charcoal canister that holds the gasoline fumes from the fuel system lets in too little fuel. When this code shows up, you might be able to smell gas coming from the car. The P0411 code usually goes away after the broken purge valve is changed or a clogged connector line is taken care of.
System Too Lean (P0171, P0174)
A fuel mixture is said to be lean when an engine is not getting enough gasoline and oxygen to burn it. If an engine runs lean, it may not make as much power or run smoothly. This code is set off when the front oxygen sensors of the car detect a lean state.
Fuel Trim System Rich (P0172, P0175)
These codes show that the reverse of a lean condition is true. A cylinder in an engine that is running excessively rich has too much fuel in it. The oxygen sensor also helps find this problem. Black smoke from the exhaust and bad gas mileage are two signs of a rich condition. You might also notice that the car hesitates when you speed up or that it doesn’t start because the spark plug is soaked in gas.
Additional Phoenix Considerations
Elevation and the heat of the desert can cause additional stress to emission and exhaust systems in our climate compared to more temperate locations. Also, if your vehicle is only used seasonally, issues such as deposit build-up, moisture condensation and carbon loading can all contribute to less durability. Just another reason why here in Phoenix, catching engine problems early with regular maintenance and finding out what is going on when a check engine light comes on is so vitally important.
