Written By: Art Jacobsen firstname.lastname@example.org
In today’s Fault Code Spotlight I will explain one of the most common and severe fault codes in your vehicle – misfire. Misfire is a very serious problem and one you should never ignore. The fault codes that you will see for misfire are:
P0300- Random/Multiple Cylinder Misfire Detected
P03nn – Cylinder nn Misfire Detected where nn is a 2 digit number (01, 02…11, 12) indicating the cylinder in your vehicle 1-12.
P0313 – Misfire detected due to low fuel level
P0314 - Misfire detected single Cylinder not determined
P0315 -Misfire Detected due to crankshaft position sensor
P0316 – Misfire detected during engine startup
The most common method for detecting misfire is called crank pulse fluctuation. At an engine speed of 7,000 rpm, your vehicle’s computer is processing 2,800 crank pulses every second! The onboard computer works with the crank pulse sensor to look for fluctuations in the signal to determine if your engine is misfiring. It then triggers the check engine light if it sees a problem.
There are two types of check engine light warnings that all drivers need to be aware of. The first – and more severe is a Type A misfire, which is represented by a flashing check engine light. This flashing check engine light means you are doing “mechanical damage” (read in a deep ominous voice designed to imply very large repair bills by continued neglect) to your vehicle if you continue to drive under these conditions. If you see a flashing check engine light you should seek immediate professional advice.By mechanical damage we are talking about things like the catalytic converter, the exhaust manifold, pistons, rings, valves – virtually all upwards of four-digit repair bills.
During misfire, raw fuel is being passed through your vehicle’s engine. This fuel actually ignites and starts a fire in your exhaust manifold and catalyst. This drives the temperatures up in excess of 1000̊C causing the ceramic in your catalytic converter to begin melting. It can crack your exhaust manifold, damage sensors, and much more. If you see a flashing check engine light, you need to act IMMEDIATELY to save your vehicle and a lot of money.
The second type of misfire is a Type-B misfire. This means that your vehicle is misfiring enough to cause the emissions from your vehicle to be over 1.5 times the emission standard. While it’s less severe than Type-A, you still need to address this failure quickly. Small misfire can lead to big misfire very easily.
There are literally a hundred different things that can cause misfire, and trying to figure them out can be mindboggling. Plus, a misfire is just one of hundreds of systems that your vehicle’s on board computer is managing. The amount of computing power in today’s vehicles is truly amazing. They are far more sophisticated than the computers on board the Eagle Lunar Lander that took us to the moon.
This is where the value of CarMD’s proprietary database can help you pinpoint exactly what is wrong with your car and get it fixed right the first time. All too often people will start throwing things at a vehicle that is misfiring trying to fix it. Have you ever heard any of the following?
“Oh you must have had some bad gas … fill up with premium next time or try this injector cleaner,” or
“Misfire is usually spark plugs. Let’s change those out. How ‘bout the plug wires,” or even
“Could be an injector; let’s change those out.”
CarMD gives you access to our vast network of ASE master technicians. You draw on the knowledge and experience of everyone that has gone before you. Let’s say you have a 2003 Honda Accord with 140,000 miles (not uncommon by the way), and your check engine light comes on for misfire. You are not the only person that has a 2003 Honda Accord; you are not the only person with 140,000 miles; and, you are not the only person that has a check engine light on for misfire. Wouldn’t it be great to know what fixed this problem for 80% of the people who had the same condition? We have been building this database for the last 14 years and we add to it daily. In the rare event you have a problem that our database hasn’t seen yet we send it out to our network and get the right answers for you from master technicians across the country who work on cars just like yours every day.
So the next time you see flashing lights … check engine lights, that is. You will know what’s going on and what you need to do.
Mr. Jacobsen has 20 years of experience in automotive testing vehicle and product development. His work has been directly related to making vehicles and emission control systems operate more efficiently.
As director of business development for CarMD.com Corp., he is responsible for the day-to-day operations of the company as well as creating the products and partnerships that will position CarMD as the leading provider of tools and information. This empowers all vehicle owners when it comes to the health and maintenance of their vehicles.
Questions about my blog? Comment here or email me at Artsblog@carmd.com