The difficult thing with car repairs is that they are not always cut and dry. In fact, many vehicle symptoms and diagnosis codes have a variety of possible causes.

What’s more, there are a lot of myths flying around about vehicle problems and solutions. As an experienced automotive technician, I’ve found that the following ten problems are commonly misdiagnosed:

Common car problems that aren't diagnosed correctly
Car problems aren’t as easy to diagnose as some people think.

1. The vehicle is pulling to one side. The common assumption in this case is that the vehicle is out of alignment. However, an under-inflated tire can also be the cause of a vehicle pulling to one side or another. So, before you paying for a wheel alignment you don’t need, check your tire pressures.

2. The vehicle will not start. This problem specifically refers to an engine that either will not turn over or turns over very slowly. Often times, vehicle owners will hear a clicking sound when attempting to start their vehicle, and the assumptions people make are numerous.

  • Some people think a car that won’t start is a bad starter, and this is very often true, however…
  • The issue could also be a dead battery. If this is indeed the case, it’s very important to
  • Check the alternator and make sure it’s charging the battery. If not, the new battery will soon go dead and you’re right back where you didn’t start.

If you’re up for it, you can determining whether your problem is the battery or the alternator by charging your battery outside the car and then performing a load test.

3. The vehicle makes a clunking or squeaking sound when going over bumps. This is often blamed on worn front struts or shock absorbers, but it is possible that it is the stabilizer bar end links that are worn. These types of sounds are always more difficult to diagnose because there are many parts that can cause such noises. It is important to be certain of where the sound is originating from before you start making repairs.

4. The vehicle’s air conditioning is not blowing cold enough. This is commonly assumed to be low refrigerant, and the repair is to recharge with more refrigerant. However, your car may actually have a refrigerant leak. In order to determine this, a qualified mechanic should use high and low pressure gauges. Simply charging the system without testing this may lead to overcharging, which could damage the system and cost more money in the long run.

5. One of the most common reasons for a check engine light to come on is a bad oxygen sensor. However, even if you pull the diagnoses code from your vehicle and it indicates “oxygen sensor,” the sensor could be just fine. It could instead be an engine vacuum leak. A vacuum leak negatively affects the operation of the oxygen sensor, thus leading to the check engine code that indicates a faulty O2 sensor.

6. Unidentified leaking fluid is often assumed to be either engine oil (if dark) or coolant if some bright color. However, power steering fluid is a similar color to engine oil. One way to determine if it is steering fluid is to locate the fluid reservoir in your car and see if it corresponds roughly to where the fluid puddle is beneath the car. Automatic transmission fluid is red and oily and should not be confused for coolant.

7. The vehicle is overheating. This is often assumed to be a direct problem with the radiator, such as a leak or lack of coolant. However, another reason a car might be overheating is a faulty thermostat. It could also be a faulty engine fan. You will want to review the specific symptoms of these items before replacing the radiator.

8. The dash brake light is coming on, but your parking brake is off. This could be one of three things.

  1. The parking brake may need to be adjusted
  2. The parking brake cable is worn and  loose Y
  3. Your brake fluid is low

9. Engine lacks power. This is another issue that could be myriad of things. It could be transmission related, it could be a clogged fuel filter, or it could even be a worn cap and rotor.

10. Engine idles erratically or lopes. There are some pretty expensive repairs tied up into this problem, but the simplest thing to check is the air filter. A clogged air filter can cause an erratic idle. If the filter looks clean, time to visit your friendly neighborhood mechanic.

Bottom Line: The best way to be on top of vehicle problems is to know your car. If you take your car in for a repair and it is still displaying symptoms, do not hesitate to take it back and insist on a correct diagnosis.

About the Author: George Gibbons has worked as a mechanic at several car dealerships. Additionally, he writes for a automotive blog. If you’re interested in learning more about him visit this useful site.