Find reliable auto repair near you.

Consumer Repair Guide
Car Computers

Times have changed and so have cars. Computers are smaller, more powerful and more complex every year. This allows auto manufacturers to use computing power to optimize engine performance and monitoring.

Assuming your car was built after 1981, there are several computerized functions regulating its performance, including:

  • An engine control computer that responds to input from sensors located throughout the vehicle, including throttle position sensors, vehicle speed sensors, coolant temperature sensors and air conditioning system pressures.
  • One or more microprocessors that receive input from these sensors to control emissions and fuel economy.
  • The microprocessor in turn controls actuators and relays that set idle speed, shift the transmission, control the fuel pump, fuel injectors, the engine cooling fans and air conditioning system.

Electronics now control more than 86 percent of all systems in your vehicle. Electronics make cars more enjoyable and reliable, but also more complex. The complexity of your vehicle makes diagnosing a problem much more challenging. For example, the electrical connection, power supplies, and grounds can corrode and cause a host of problems that can be difficult to track down. Diagnostic tools are better than ever, but diagnosing repair needs today can be more time-consuming -- and expensive -- than in the past.