Properly completing vehicle repairs is practically impossible without troubleshooting and diagnosing the problem – or problems – with your vehicle. To determine the cause of a particular automotive issue, you need to know a few troubleshooting techniques. To help you complete your vehicle troubleshooting, we will delve into various troubleshooting procedures that will enable you to diagnose and fix common issues with your car, truck, or SUV, as well as to help you better understand problems that may require a professional to address. Whether you’re experiencing engine trouble, electrical or mechanical faults, or simply have a desire to learn more about DIY problem-solving, we've got you covered. We'll also share a few helpful preventive maintenance and troubleshooting tips to help you avoid future issues. Our mission is to provide you with the insights and resources necessary to keep your vehicle driving safely and at its best. If you need a helping hand when it comes to Check Engine light troubleshooting, visit any O’Reilly Auto Parts store and ask about our O'Reilly VeriScan service to get your to get your Check Engine light scanned for free by one of our parts professionals.
Troubleshooting Common Car Issues
Proper vehicle maintenance requires an understanding of common car problems that you might experience. Being aware of the most common car issues can help you spot them early and take necessary action to mitigate further damage. The first step in automotive troubleshooting is knowing how to identify common issues, recognize the symptoms associated with them, and pinpoint their initial cause. These can range from straightforward issues such as a dead battery or a blown fuse to larger and more complex problems like engine misfires or transmission failures. By being familiar with these common problems, you can save both time and money by addressing them quickly and efficiently.
Being able to recognize the symptoms of common car issues is key for accurate diagnosis. While symptoms may vary depending on the specific problem, most issues often include an illuminated Check Engine light, warning lights on the dashboard, odd noises, unusual vibrations, or diminished vehicle performance. By noticing these signs quickly, you can begin troubleshooting by narrowing down any potential causes and recognizing appropriate repairs.
Determining the cause of car problems is a crucial part of effective troubleshooting. While many symptoms provide valuable clues, it's often necessary to dig deeper to find the underlying issue and complete needed repairs. This may involve conducting diagnostic tests, inspecting specific vehicle components, or seeking professional advice. By identifying the root cause, you can often directly address the problem and prevent it from recurring.
Troubleshooting Engine-Related Issues
Engine-related problems with your vehicle can be both frustrating and inconvenient, and can often result in reduced vehicle performance and poor fuel efficiency. However, with the right troubleshooting techniques, you can quickly identify and address these issues to not only make needed repairs, but also prevent further damage from occurring. Read below to find three common engine issues and how to diagnose them.
Engine Won’t Turn Over
A common engine issue is difficulty starting your vehicle. If your engine won't turn over there may be one or more reasons. Begin troubleshooting by checking your battery connections to ensure they are secure and free of any debris or corrosion. You can also have your battery tested for free at your local O’Reilly Auto Parts to ensure it is fully charged and up to the task of starting the engine. If the battery is in good health, but isn't fully charged, you may have an issue with the alternator, which recharges the battery, or the battery cables, which deliver voltage to the battery. If the battery is fully charged and the engine still struggles to turn over, this likely points to a problem in the starting system, including issues with the starter, starter relay, battery cables, or even the ignition switch.
Engine Won’t Start
If the engine is turning over as it should but the engine won’t start, the problem might lie within the ignition system or fuel delivery system. To troubleshoot these systems, inspect your vehicle’s spark plugs, test your ignition coils to determine if power is reaching the spark plugs, and check your fuel pump for any signs of malfunction by listening near the tank to determine if the fuel pump is running. After thoroughly inspecting each part, you may be able to simply replace the worn or damaged components to resolve the starting problem. If the source of the problem is still unclear, further diagnosis may be needed.
Engine Misfiring or Stalling
Engine stalling and misfiring can occur while idling, accelerating, or decelerating. Engine misfires often cause Check Engine light codes indicating which cylinder is experiencing the misfire. From there, you can often narrow down the problem area. Stalling is a little more complicated, but any sensor that is out of specification (MAF, oxygen sensors, MAP sensors, and more) will typically result in a Check Engine code to help get you started. To diagnose this problem, start by inspecting your vehicle’s air intake system for any blockages. A dirty or faulty mass air flow (MAF) sensor can cause stalling and rough or erratic idle. Cleaning and replacing your MAF sensor can help prevent engine stalling while also preventing further engine damage from occurring. It’s also a good idea to check your vehicle’s fuel system for issues such as a blocked or clogged fuel filter, a faulty or clogged fuel injector, or a damaged fuel pump relay, which can lead to reduced engine performance or a complete lack of fuel pressure. Many fuel systems have a test port valve that can be used along with a fuel pressure tester to determine if adequate pressure is reaching the fuel rails, which can assist you in determining the source of the problem.
Engine Overheating and Noise
Engine overheating and abnormal noises coming from under your hood are indicators of potential engine problems. To troubleshoot engine overheating, check the coolant level and ensure there are no leaks or signs of damage throughout your vehicle’s cooling system. This includes inspecting the radiator hoses, water pump, heater hoses, radiator, and more. Without the right amount of coolant circulating through your engine, it is more likely to overheat. A malfunctioning thermostat or a faulty radiator fan can also cause engine overheating and should be repaired quickly to avoid permanent engine damage. Unusual noises coming from your engine, such as squealing, clunking, or ticking, can also be caused by various factors such as loose or worn belts, worn-out bearings in the alternator, water pump, power steering pump, or A/C compressor, or exhaust leaks. Inspect these components and replace any damaged parts to eliminate noises and prevent engine damage and overheating. Ticking noises or other sounds from the inside of the engine may also point to low oil levels, and checking the level and condition of your oil can help determine if this could be the cause. In some cases, internal engine damage may cause noise that won't be affected by adding or changing the oil, but this is a good first step towards diagnosing the severity of the problem. For more resources to help you troubleshoot problems with your vehicle’s cooling system or engine and drivetrain, visit our How-To Hub.
Troubleshooting Electrical and Mechanical Malfunctions
Being able to identify and repair electrical and mechanical problems is crucial when troubleshooting vehicle issues. To learn more about some of the most common electrical and mechanical problems you might encounter and how to resolve them, read on.
Electrical Problems
Troubleshooting electrical problems can be tricky if you’re not sure where to start. Electrical issues can cause a wide range of symptoms, from a dead battery to malfunctioning interior and exterior lights or failing power windows, power door locks, accessories, and more. A common indicator of electrical issues in vehicles is blown fuses. To locate the cause of the issue, check the fuses and relays related to the failing components. If the fuses are intact and the relays are working as they should, it’s typically a sign that no short-circuiting is occurring. If the fuses are blown, on the other hand, it’s a good idea to use a multimeter to test the electrical connections in the circuit and inspect for any bare or frayed wires in the wiring harness. By systematically checking each component, you can begin to identify and fix the problem. To learn more about how to test automotive relays, check out our helpful article.
Ground drain issues are also a common cause of electrical system problems in a vehicle, and often cause the battery to lose charge when the vehicle sits for long periods. Similar to short circuits, ground drains can be caused by damaged or broken wires that allow power to be siphoned from the battery when the vehicle isn’t running, or they may be caused by damaged internal electronics in an accessory system like the radio, courtesy lighting, and more.
The best way to test for ground drain is to remove the positive battery cable and connect a multimeter set to measure amperage between the terminal and the battery post. Any amperage draw higher than 50mA is enough to rapidly drain the battery, and is an indication that a circuit is drawing excessive power. To narrow down which circuit is causing the ground drain, pull fuses one at a time and watch the amperage reading on the multimeter. If it drops significantly when a fuse is removed from a specific circuit, that circuit likely has an electrical issue that requires further diagnosis and repair.
You should also be able to troubleshoot issues with lights, windows, and doors. If your vehicle’s interior or exterior lights are dim or flickering, but inspecting or replacing the bulb doesn’t indicate that the old bulb was damaged, it could be a sign of a failing alternator or a loose or damaged electrical connection. If your power windows aren't functioning properly, inspect the window switches, wiring, relay, and motor for damage. For problems with doors, such as difficulty opening, closing, or locking, check the door latch and hinges for any signs of damage or misalignment. It may also be necessary to inspect the power door lock actuator if your doors won’t lock or unlock properly, as a damaged or stuck actuator can prevent even the manual locking system from working as it should.
Brake Issues
Faulty brakes are one of the most common mechanical issues experienced in a vehicle. This mechanical fault can significantly impact performance and safety, and repairing the braking system should be a priority. If you experience brake issues, such as grinding noises or a pulsating brake pedal, it could be due to worn brake pads, damaged or worn brake rotors, or a caliper that has become stuck and is causing the brakes to drag. A spongy brake pedal or one that sinks to the floor when you apply pressure can be caused by brake fluid leaks, air in the brake lines, or a damaged master cylinder, caliper, or brake hose. If you notice any of these symptoms, inspect your vehicle's brake fluid levels and check your brake pads and rotors for wear or damage. This can help you begin to determine the cause of your brake issues and complete any necessary repairs as soon as possible to keep you and your vehicle safe on the road. It is often a good idea, especially if you don’t know when the brakes were last serviced, to bleed the brake system and replace the brake fluid with fresh, clean fluid. Because brake fluid is hygroscopic, it absorbs water over time, which can make the brake pedal feel soft and diminish braking ability throughout the life of the brake fluid. Water in the brake fluid can also lead to brake line corrosion, and this may eventually cause leaks and pressure loss.
Transmission Issues
For transmission issues like slipping gears or hesitation, check the transmission fluid level and condition first before continuing your diagnosis. Low transmission fluid levels can cause a host of issues with transmission operation, and damage in the transmission itself can cause the fluid to burn. Transmission problems in modern vehicles may also trigger transmission-specific trouble codes, and this may require a special scan tool to fully diagnose. If you don’t have an OBD-II scan tool available, stop by any O’Reilly Auto Parts location and get your diagnostic codes checked for free with our O’Reilly VeriScan service. If the transmission codes are not displaying, this may require a professional shop with the proper equipment to pull the codes and begin the diagnosis.
Suspension Problems
Suspension failure symptoms, such as excessive bouncing, difficulty steering, or uneven tire wear, might indicate worn shocks or struts or poor alignment. Suspension noise, including clunking or popping noises when turning, squeaking or chirping when driving over bumps, excessive body sway, or a loose steering wheel could indicate issues with your ball joints, tie rods, sway bar links, bushings, or other parts of the steering and suspension system. Consult your vehicle's service manual for specific troubleshooting steps and consider seeking professional help to diagnose suspension system wear and failures if necessary.
Essential Tools and Equipment for Troubleshooting
Before diagnosing car problems, it’s important to gather the necessary tools and equipment. A basic tool kit should include items like a wrench set, ratchet and socket set, multimeter, and jumper cables. A code reader or OBD-II scanner to access your vehicle's diagnostic trouble codes (DTCs) can also be helpful. For more information on what common Check Engine light codes mean, take a look at our article.
Diagnosing Car Problems
Start by identifying the symptoms and researching potential causes online, in a service manual specific to your vehicle, or your vehicle’s owners manual. Follow a systematic approach to narrow down the possibilities. Depending on the problem, troubleshooting may involve inspecting components, testing electrical connections, or using diagnostic tools to read DTCs. Take note of any error codes or unusual sounds, smells, or vibrations.
Safety Precautions and Best Practices
Safety should always be your priority when troubleshooting car problems. Park your vehicle on a level surface and engage the handbrake, especially if you will be lifting or working underneath the car. Wear protective gear such as gloves and safety glasses, and avoid working underneath a vehicle that is only supported by a jack; use jack stands in the appropriate locations underneath the vehicle for added stability. Disconnect the battery when working on electrical components and be wary of hot engine parts.
By following these tips, you can confidently troubleshoot and diagnose common car problems. Remember, if you encounter a problem that's beyond your expertise, it's always best to consult a professional mechanic. If you determine that you need help, O’Reilly Auto Parts can recommend a trusted service center in your area.
By following these preventive maintenance and troubleshooting techniques, you can ensure your vehicle remains reliable and safe throughout its life. Remember, these troubleshooting techniques are meant to provide general guidance. Always refer to your vehicle's manual for specific instructions and safety precautions. If you need clarification on any repair procedures, it's recommended to consult a professional mechanic or visit your local O'Reilly Auto Parts store for assistance. We offer free Check Engine Light testing to help you accurately complete your troubleshooting. We can also recommend a local shop to help you complete your repairs. At O'Reilly Auto Parts, we offer a wide range of automotive products to help you maintain and troubleshoot your vehicle. Browse our selection of parts, tools, and accessories to keep your car running smoothly.