Blog

Starting in 1996, our service technicians have been able to use a standardized diagnostic system to help figure out what is wrong with a vehicle. This diagnostic system works together with the Engine Control Modules for each vehicle's engine. The Engine Control Module is a computer that monitors and controls many engine functions.

Sensors throughout a vehicle will send readings to the Engine Control Module. These readings help the computer make adjustments in various vehicle systems to allow for constant changes in driving conditions and will even compensate for minor issues. However, if the computer runs into a situation it can’t fix, it turns on the Check Engine light. (The Check Engine light may be called the “service engine soon” light on your vehicle.)

If you see the Check Engine light on your dash, it means you have a problem that needs to be taken care of soon. If it is flashing, the vehicle needs immediate attention at Hilltop Tire Service. When the Check Engine light is flashing, the vehicle should not be driven at high speeds, haul heavy loads or tow a trailer. Drivers need to understand that doing this can cause major damage.

When a vehicle is brought to Hilltop Tire Service in Des Moines because the Check Engine light is on, a technician will scan the Engine Control Module to find out why it turned the light on. The answer shows up as a “trouble code.” Our technicians have access to software that allows him to enter the code and find out what it means. The software will also let your technician know what could be causing the issue and how to diagnose it.

Notice that the trouble code does not tell our technician exactly what is wrong with the vehicle. It will only let him know where to start looking to locate the problem.

Scanning a trouble code and determining what it means is fairly simple for the pros at Hilltop Tire Service. But the process of actually diagnosing a vehicle's problem can take a skilled technician some time. Sometimes this can add up to a significant repair bill. Some vehicle owners mistakenly believe that the “trouble code” is all they need and think they can then fix the problem themselves. Some have tried to save money by purchasing an inexpensive scanner, or they take their vehicle to an auto parts store that offers the scan for little or no cost.

These options are often not the money-savers they seem for Des Moines vehicle owners. They can end up costing the vehicle owner extra in unnecessary repairs or even engine damage.

For example, the trouble code P0133 reads “Bank 1 sensor 1 circuit slow response.” Translated, that means the front oxygen sensor shows a slow response time in changing the mix of air to fuel. The seemingly obvious conclusion is that the sensor needs to be replaced. The vehicle owner purchases a sensor, installs it and happily goes on his way.

However, read the trouble code again: a slow response time in changing the mix of air to fuel. Nowhere does this indicate that the sensor is bad. There are a lot of parts involved in changing the air-fuel mix, any of which could be causing a slow reaction time. Those include a contaminated or bad airflow sensor, an exhaust leak, a problem in the electrical system or a leak in the intake manifold. The sensor is just relaying that the response time is slow; it does not indicate where the issue is.

So the vehicle ends up with an oxygen sensor it did not need, and the delay in repairing the actual problem may have led to further damage to the engine. Both are added costs for the vehicle owner.

Cheap scanners also don't have the ability to read the history stored in an engine's computer. The operating history contains clues that can help in diagnosing engine trouble since it can indicate a developing problem. Here at Hilltop Tire Service, we invest a lot of money in high-end diagnostic equipment so that we have access not just to service codes but also to the operating history of the engine.

On-board diagnostics, then, are a tool to help diagnose what is wrong with a vehicle. They cannot specify what part needs to be fixed or replaced, and they cannot replace a well-trained and well-equipped service technician.

Unless you are a trained mechanic, it's a good idea to use Hilltop Tire Service for your car care. In the long run, it can save you time, unnecessary expense and frustration. Hilltop Tire Service can also help you keep up with your scheduled preventive maintenance, which can also save you on repair bills by alerting you to potential problems before they get expensive.