Women Starting a car

How To Start/Stop A Car And What To Do When It Doesn’t Work

Starting a car may seem like a simple task for most car owners. However, the simple act of turning the ignition key activates many systems and components at the same time. If any of the sensors, switches, or safety features become faulty, it may prevent the engine from starting altogether. If you are having problems starting your car, there might be something wrong with the ignition switch or another related component. To help you find out what the problem is and prevent future expensive repairs, here’s how to start/stop a car the right way as well as what to do when it doesn’t work anymore.

Steps to Starting a Car

The Ignition Switch

Cars and trucks have two basic types of ignition switches. The most common type of switch uses a key that is inserted into the lock to start the car. The second type, which is seen more and more every year, is called a keyless ignition. Instead of a key, this system uses a transponder to start the engine. The car will recognize the transponder as the driver enters the car and all he has to do is to press the start button.

Ignition Switch Positions

How to start/stop a car

On vehicles equipped with a lock switch, the ignition key can turn to several positions, each having a specific function.

When the key is inserted, it’s in the OFF position by default. The “ACC” or Accessory position, also sometimes identified by an “I” symbol, is usually one position to the right or to the left from the OFF position. Turning the key to Accessory will turn on some essential electric components like the radio, power fool locks, etc. On some vehicles, the heater blower and wipers could work.

One more position to the right is the ON position (II). When the key is ON, all electric and electronic components are active. This is also the position where the key returns to after starting the engine.

Last but not least is the START (III) position and, as its name implies, turning the key to this position activates the starter relay and solenoid, effectively starting the engine.

Starting the Engine

When the key is turned to the START position, the starter’s electrical circuit is closed and the starter begins to spin. You should only turn the key to the start position for a limited time. If you hold the key in the start position while the engine is running, you may damage your starter or the flywheel’s teeth.

If you own a higher mileage or carbureted car, it can be a little more difficult to start. Carburetors usually take more time to ignite and pressing the gas pedal may sometimes help. If you need to hold the key to the START position for an extended period, your car might have another problem. A depressurized fuel system or faulty cam sensor, for example, can increase the cranking time required to start the engine.

Common Cause Why the Car Won’t Start

Over the years, car manufacturers have come up with all sorts of innovative features designed to prevent failures and accidents when starting a car. Just imagine, only 100 years ago, drivers had to start the car by hand. And today, you can just keep the key in your pockets and push a button.

However, some components may become faulty at one point and may prevent the car from starting. Here are some of the most common causes of why the ignition may prevent the car from being operational.

Steering Wheel Lock

Most cars have a device within the steering column that locks the steering wheel in place when the key is not in the car or in the OFF position. Reversely, the ignition key will also not turn when the steering lock is engaged. To unlock the steering wheel, you’ll need to pull and turn the steering wheel slightly to disengage the lock and only then turn the ignition key to start the car.

Neutral Safety Switch/Clutch Switch

Cars with automatic transmissions must be in Park or Neutral to start. The neutral safety switch keeps the starter relay open to prevents the engine from being started while engaged in gear. Starting a car equipped with an automatic transmission while on the DRIVE position would cause the car to lurch forward as soon as the starter is activated.

The same thing is true with vehicles equipped with manual transmissions if only that, this time, the safety switch is installed on the clutch pedal. This system ensures that the driver effectively has its foot on the clutch pedal, keeping the car on Neutral. Clutch pedal and neutral switches, when faulty, will both prevent the car from starting.

Ignition switch circuit diagram

If your car doesn’t start because of a defective clutch switch, you can always bypass the switch using jumper wires or by connecting both wires together. Doing so will provide a power input to the starter relay and the car should start. However, we highly recommend replacing the switch as soon as possible.

On a car equipped with an automatic transmission, you can’t really bypass the neutral switch since you’ll need it to engage the gear once the engine is started. A nice trick, though, is to put the gear stick in Neutral instead of Park an try it. If the Park position signal is the faulty one, starting it in Neutral might work. If it doesn’t work, the switch will need to be replaced before moving the car or you might have to call for a tow truck to bring it to the nearest auto repair shop.

Brake Switch

Automatic transmission vehicles also need the brake pedal to be depressed and the brake switch signal to be activated for the engine to start. A faulty brake switch will create the same symptoms as a faulty neutral/clutch switch. Consequently, the same trick can also be applied to start a car with a defective brake switch. Simply bypass the switch and you should be good to go.

Ignition Lock

Sometimes, especially with older cars, it may happen that the ignition lock simply doesn’t turn, even if the steering lock is not engaged. That might be because some of the pins inside the lock are damaged. When it happens, spraying a bit of lubricant inside the lock and lightly hitting the key towards the lock while applying some pressure might help.

In all cases, having your lock checked out by a locksmith is probably your best bet. When locks start becoming hard to turn, they rarely get better with time.


Ignition Switch

The ignition switch is, in fact, multiple switches into one. It supplies current and provides inputs to power every single electric system in the vehicle. Consequently, if any of the contacts wear out or the ignition switch is faulty, some systems may stop working. If the starter relay’s contact is damaged, for example, the starter won’t spin even when the key is turned to the START position.

Replacing an ignition switch
Replacing an ignition switch



Other Causes

Obviously, many other components unrelated to the ignition switch could prevent the engine from starting. Here are the most common ones:

In fact, most components could prevent an engine from starting, from a bad sensor to a blown head gasket. An engine includes thousands or part and most of them are essential to its proper operation.

Grinding Noise When Cranking

There are few sounds more alarming than when you accidentally try to start a car that is already running. Luckily, to prevent the starter from being damaged if it’s engaged while the engine is running, manufacturers have incorporated a neat feature in the starter, called a freewheel.

The freewheel is simply a gear that is engaged in one direction and can spin freely in the other. However, even if the starter won’t be damaged, the same is not true for other components. The loud, screaming sound you hear is your starter grinding against the flywheel and ring gear. If the starter pinion grinds for too long, it might damage some of the teeth that could fall into the transmission bell housing.

Turning a Car Off

Never forget that you should always come to a complete stop before putting the transmission in Park or turning off the engine. Doing so will most likely damage some of the transmission’s internal components. Furthermore, shutting off the engine will also turn off the power steering system and may lock the steering wheel, which may result in a loss of control.

You can turn the key to the OFF position once the car is stopped and is in Park. Once the car is shut off, remove the key as leaving the key in the ignition may drain the battery on some car models.

Reasons the Engine Won’t Stop

A car that won’t stop running when the key is off is not a common occurrence but it may happen. The main reason you will have an engine that won’t turn off is a faulty ignition switch. If that’s your case, you can always pop the hood and remove any of the main switches or the fuel pump relay to force the engine to die.

In all cases, you should replace your ignition switch as soon as possible. The parts are typically cheap, and replacing an ignition switch is pretty easy. If you plan to do it yourself and save some money, get your hands on your car’s repair manual first. Some vehicles may have a specific procedure to disassemble the ignition switch or remove the steering column. Following the manufacturer’s recommended procedure will ensure you get the job done right the first time.

A condition called engine run-on or dieseling can happen that causes an engine to keep running for some time after the key has been turned off. This is usually a problem related to self-ignition related to improper fuel delivery.

How to Start/Stop a Car with a Bad Ignition Switch

Learning how to start/stop a car the right way and how the starting system works on your car will not only prevent damaging expensive components but it will also help you figure out what’s wrong when it doesn’t work as intended. Mastering the basics of auto mechanics is also your best bet to save on your vehicle maintenance and repairs. When in doubt, don’t hesitate to consult your car’s repair manual. In the dedicated section, you’ll find many troubleshooting charts to help you quickly identify and locate the faulty component. Once you’re there, it’s super easy to just follow the instructions, replace the part, and save money.

Good luck!


About Derek F

Derek grew up in Southern California and started working on cars when he was a child. He learned from his father and grandfather how to make basic repairs and maintain cars correctly. Derek rebuilt his first engine at 15 years-old, beginning an automotive career that took him to many interesting jobs. Derek has worked as an automotive detailer, managed parts warehouses and auto parts stores, and worked as a mechanic for several years doing brake and suspension work. While pursuing a bachelor’s degree in government journalism, Derek worked for an auto museum where he started to write about cars. Today, Derek uses his expertise gained from many years of practical experience to help educate DIYers and share interesting knowledge about various types of automotive repair and service. Writing about cars helps fund his numerous classic car restoration and customization projects.

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