10 Most Common Car Problems


May 3, 2016
10 Most Common Car Problems
“What are the most common car problems you deal with in your repair shop on a daily basis?” is probably the most frequently asked question I encounter almost daily. While there is no simple answer to this question because different types of vehicles develop different types of faults, there are nevertheless some faults that are common to most vehicle types and styles.

Thus, the purpose of this article is to list the 10 most common car problems/faults that are often easily preventable simply by sticking to recommended maintenance/servicing schedules either by professionals, or in some cases, by vehicle owners themselves. Let us start with-

Non-starting conditions due to battery issues
While modern automotive electronics have developed rapidly over the last 10 - 15 years, the development of automotive batteries has not. Most batteries are still built to last for only 3 – 5 years, which can be severely reduced by environmental factors such as extremes of temperature. The causes of premature battery failure are many and varied, but for the most part, these include-

· Excessive current drains caused by keyless entry / ignition systems

· Current draws by (often defective or poorly installed) tracking devices

· Poor maintenance of battery terminals and cables

· Failure to inspect electrolyte levels regularly

· Defects in the charging system, with defective alternators being the most common problem

· Use of unsuitable, or incorrectly rated batteries, and especially on diesel-powered vehicles

· Use of unauthorized, or poorly installed aftermarket accessories such as audio systems and auxiliary driving lights

Engine overheating
While engines sometimes overheat through factors that are outside of the car owner’ control, such as when a radiator is punctured by road debris, most cases of engine overheating can be directly attributed to poor maintenance.

However, while it is true that items such as water pumps, thermostats, and radiators themselves are not service items and are therefore not subject to regular replacement, other items such as heater valves, radiator hoses, and radiator/expansion tank caps are common sites of coolant leaks that can cause rapid coolant loss if leaks are left unresolved.

Engine overheating cannot always be prevented, but the average car owner can greatly reduce the risk of it happening by-

· checking the engine coolant level at least once a week

· making sure that the antifreeze / coolant is always mixed strictly in accordance with the manufacturer’s specification

· inspecting the engine for fluid leaks

· Inspecting the water pump drive belt and radiator hoses for signs of damage / leaks at least once or twice per month

· Immediately making repairs or replacing components when a coolant leak is found

Transmission issues
Modern automatic transmissions may have improved the general driving experience greatly, but this seems to come at the expense of increased unreliability. However, this is not always due to transmission failure, but in many cases, because of the failure of one or more sensors or control modules that directly control the transmission.

Any transmission issues such as transmission slippage, and/or harsh, erratic, or unpredictable shifting must be investigated immediately, since in some cases, sensor or control module failure can cause irreparable harm to the transmission if the root cause of the failure is not resolved or addressed. In some cases of sensor/control module failure, the transmission may be forced into a fail-safe or limp mode until the problem is resolved.

Nonetheless, most transmissions require regular fluid and filter replacements, and more often if the vehicle is used for towing boats and trailers. Keeping to the recommended fluid replacement schedule may not prevent all transmission failures and issues, but it will go a long way towards increasing the reliability of the transmission.

Oxygen or air/fuel ratio sensor failure
The primary purpose of these sensors is to both control the air/fuel mixture, and to monitor the functioning or efficiency level of the catalytic converter(s). However, oxygen-, and air/fuel ratio sensors have finite service lives of about 100 000 miles or so, but issues such as excessive oil consumption, use of poor quality fuel, wiring issues, or engine vacuum leaks that affect proper engine operation can greatly reduce the useful life of these sensors.

Note also that sensor failure can cause catalytic converters to fail, which may not be replaceable under federally mandated warranty conditions if the catalytic converter failure was caused by say, excessive oil consumption or shorted oxygen sensor wiring.

Uneven/accelerated tire wear
The inclusion of this item may come as a surprise to some, but the fact is that the combination of bad roads, potholes, and advanced/complex suspension systems can reduce tire life by as much as 40% on some vehicles.

Proper alignment of the wheels on one axle and the wheels on both axles relative to each other does not only improve steering and braking responses; it also improves the vehicle’s handling characteristics under hard cornering. However, poor maintenance and servicing often leaves worn or damaged steering and suspension components undetected/unrepaired/unreplaced, which can have serious negative consequences both on how long (or otherwise) tires last, and on fuel economy because one or more wheels are misaligned relative to the other wheels.

Note that in some cases, poor wheel alignment is the result of poorly repaired accident damage, or worse, sloppy assembly procedures when the affected vehicle was built. In the latter case, it may be impossible to correct the problem.

The most common signs of mis-aligned wheels are-

· the vehicle pulls to one side even on level roads

· the vehicle pulls to one side under braking

· the vehicle “wanders” across the road

· The front wheels do not automatically return to the straight ahead position after turning

Brake system issues
Modern brake systems have reached a very high level of sophistication, and it seems that every new development brings along a new set of issues. However, many brake system issues stem from poor maintenance, and simply replacing the brake fluid every year can prevent a lot of potential issues.

Nonetheless, brake system problems are relatively common even on new vehicles, and these generally include poor braking performance, brake shudder, uneven braking, or non-functioning ABS systems. Finding and repairing the root causes of these problems on new vehicles is not always easy, but any brake system issues should be referred to the dealer immediately for professional diagnosis and repair, since the entire brake system could fail unexpectedly if the problem is not resolved.

Electronic failures
This item covers a lot of ground, but for the purposes of this article, it refers mainly to issues such as failures of rear-view cameras, infotainment and navigation systems, power windows, power seats, sunroofs, and the like.

Many of these types of failures result from wiring issues such as poor electrical connections, and short circuits, but also from corrupted software, poor systems integration, or abnormally high or low system voltages and particularly those cause by incorrect jump starting procedures. In many cases, these issues can be resolved by installing updated software or dedicated software “patches” to repair known programming glitches and vulnerabilities. However, these procedures should not be attempted if suitable or the required equipment and software is not available.

NOTE: This item also includes the failure of key fobs either to allow entry into the vehicle, or failure to start the vehicle. While a simple key fob battery replacement will often cure the problem on older vehicles, the issue may require professional diagnosis and repair on newer applications.

Ignition coil and spark plug issues
While issues with defective spark plugs are very often the result of poor maintenance and skipped services, ignition coils are (with a few exceptions) generally not service items, and therefore not subject to regular replacement.

However, high under-hood temperatures and high voltages eventually combine to break down the insulation around the windings in ignition coils, which when it happens, causes the coil to perform poorly, or more commonly, to fail completely. Failed or failing ignition coils almost always produce misfire related fault codes, which makes identifying the problem coil a whole lot easier. Note though, that ignition coils are NOT repairable, and replacement with OEM parts is the only reliable remedy.

EVAP system failures
While any failure in the EVAP (Evaporative Emissions Control) system will produce an illuminated CHECK ENGINE light, the good news is that in many, if not all cases, the issue is nothing more than a leaking gas cap that allows fuel vapors to escape into the atmosphere. Since the gas cap is removed and refitted thousands of times during a car’s life, it is reasonable to expect that it will fail at some point, so diagnostic procedures for any EVAP system codes that relate to leaks should start with an inspection, but preferably, the replacement of the gas cap.

Other common EVAP issues include failure of the charcoal canister, vent-, and/or purge valve(s), perforated or dislodged vacuum lines, and/or wiring issues such as abnormal resistances or open circuits.

Mass airflow sensor failure
The purpose of this sensor is to monitor the volume of air that enters the engine, and without accurate input data from this sensor, the PCM (Powertrain Control Module) cannot control the air/fuel mixture effectively.

While the MAF sensor can fail for a variety of reasons, and usually at inopportune times, the most common reason is oil contamination of the heated sensing element, and especially on applications such as BMW, Mercedes, Audi, and other VAG-group applications that are notorious for their high oil consumption rates. On these applications, a simple cleaning of the element with an approved solvent will often resolve the issue, but in most other cases, replacement of the MAF sensor with an OEM part is the only reliable remedy.


Mar 27, 2018
good read