Today, we will talk about on-board diagnostics (OBD) and some of the questions we hear from folks who need answers about diagnostic services. They want to know what diagnostics are, what's involved and what the benefits are. They want to understand the value of diagnostic scans by a trained technician. These are valid concerns. If you don't understand something, it's tough to know its value.
Since 1996, all cars and light trucks use a standardized diagnostic system to help all repair technicians determine what's wrong with your vehicle. The diagnostic system works with the vehicle's Engine Control Module – the computer that controls many engine functions. The computer monitors dozens of components and processes. Depending on what the sensors read, the computer will adjust to compensate for conditions and minor problems. When there is a condition that it can't compensate for, the computer will turn on the Check Engine light. The Check Engine light is also called the Service Engine Soon light on some vehicles. The warning light signals you to get into your local service center to diagnose and repair the problem. Your service center will likely have a scan tool and powerful software to help the technician diagnose the problem. If you've searched for Check Engine light on the internet, you may have seen that you can buy an inexpensive code reader or go to an auto parts store to have the trouble code read to tell you exactly what's wrong. That's a common myth. The code itself doesn't tell you exactly what's broken. It starts you looking in the right place. It describes what engine parameter is out of range – but it won't explain what's wrong or how to fix it. Let's say you think your child has a fever. You take their temperature, and it reads 102 degrees F/38.9 degrees C. You've confirmed a fever, but you don't know what's causing it. Is it the 24-hour flu, an infection, appendicitis or leukemia? A fever is a symptom of all of these medical problems. Still, it takes a skilled physician's examination and additional diagnostic tests to determine what is causing the fever. An example of a diagnostic trouble code (DTC) could be P0133, which reads 'Bank 1 Sensor 1 Oxygen Sensor Circuit Slow Response.' This DTC means that the signal coming from the front oxygen sensor on the bank one side of the engine has a slow response time to the changes in the air-fuel mixture. If that's all you knew about cars, you would think your oxygen sensor was broken and would replace it. Now, it could be the oxygen sensor – but it could also be a bad or contaminated airflow sensor, exhaust leak, electrical problem, an intake manifold leak or any number of other things. Many systems on the vehicle are inter-connected. The on-board diagnostics point the way to where the trouble lies, but it takes some great skill and high-tech diagnostic equipment to pinpoint the problem. The cheap code readers that consumers can buy cannot retrieve most of the detailed historical data stored in the engine computer, called freeze-frame data. That history is beneficial in diagnosing the problem. Freeze-frame data is like taking a picture of all the sensors' data at the time of a fault.
If the Check Engine light is on steadily – don't panic. Get into your local service center soon to have the vehicle diagnosed. A flashing Check Engine light means a severe engine problem or something that has failed that may be causing damage to other parts of your vehicle. Get in as soon as you can – waiting too long can lead to costly damage. And try not to drive at high speeds or haul heavy loads with a flashing Check Engine light.
On-board diagnostics provide a powerful starting place for our highly-trained, well-equipped technicians to get to the bottom of your problem. Here at ATW, we invest in high-end diagnostic tools to help solve the mystery and get you back on the road as soon as possible.
Schedule an appointment with ATW Automotive Service to have your diagnostic system analyzed by our professional technicians. We'll pinpoint the problem to save you time and money. Our technicians are certified, specially trained, and highly skilled in tackling all types of issues.