An old oxygen sensor (say, 90,000 miles or more) may still work well enough that it doesn’t trigger the check engine light but could still hurt fuel economy. Engine performance can also be reduced by more serious internal problems, such as valves that don’t seat properly or worn piston rings, or by restrictions in the exhaust system. Because the same symptoms can suggest different problems, and there are often several possible causes and cures, it’s better to consult a professional mechanic than to try to be one if you have neither the experience nor the right equipment to diagnose drivability problems. In short, rather than ask for a tune-up, tell a mechanic what you’re experiencing and ask him or her to find the cause.
There are also electrical faults in cars that are caused by gadgets in the cars, for instance audio and video systems, which consume too much power. As mentioned earlier, in as much as the exact trouble spot can be identified, repair of electrical faults in cars becomes a 'walk in the park.' The cost of repairing electrical faults in cars varies considerably; from just a few bucks to what can turn out to be quite a fortune. It helps to ensure that these faults are rectified by the right people, and the regular mechanics may not be the ideal people here; unless they also have certifications and experience in automobile wiring.
Modern cars come with complex electrical systems meaning that electrical diagnostics tools are needed in the repair and maintenance. That being said, the following are some of the most common auto diagnostic tools you will find in most auto electric repair shops. Digital motor checker - This is a vehicle diagnostic tool used in the maintenance of inbuilt electrical systems without any dismantling having to be done. This device helps in detecting problems that may result in tripping and therefore compromised electrics.
Here's what causes this: A blown fuse for the system, A wheel-speed sensor that is damaged or covered by road grime, A broken wire between the sensors and the ABS controller, An ABS controller that has stopped working. A pump and valve that apply the right amount of brake fluid pressure to each wheel to prevent locking can also trigger an ABS sensor warning light when those items go bad. If the red warning light for the regular brakes comes on, that typically means your vehicle is losing brake fluid or the brakes are so worn that you don't have normal stopping power. Either of those situations warrants immediate attention and possible repair work.