How to Get Your Car Working Again Post-EMP

The looming threat of a massive EMP has been hanging over the heads of our society, and indeed the world, for some time now.

a 1967 Ford F100 Ranger
A 1967 Ford F100 Ranger. This should hold quite nicely against even a powerful EMP!

Caused by unstoppable solar phenomena, nuclear warheads, and specialized weapons, an EMP that’s strong enough could completely disable our society, frying the electrical grid, everything attached to it, and nearly anything that relies on electronic components.

Since pretty much all cars these days depend on computers and other electronics in one way or another, and without them, they just won’t work.

It’s best to plan that an EMP, whatever its source, is going to keep you off the road. But that doesn’t mean it’s got to stay that way.

With the right approach, a little know-how, and some elbow grease, you can repair your car and get it rolling again post-EMP. I’ll tell you what you need to know down below…

Before Going Further: Assess Your Vehicle for Vulnerability

Every vehicle is different. No kidding, right? But practically speaking, what I mean to say is that every make and model of vehicle, from every era of automobiles, relies on more or less electronic equipment in order to function. This alone is a major consideration if you plan on repairing your vehicle post-EMP.

Modern vehicles, and I mean those made in the last 20 years, use tons of computers for even basic functionality, and many won’t operate at all without them.

From ECUs and transmission control modules to body control modules, electronic ignition control, various data lines, tire pressure sensors, and much, much more, there is simply a lot that can go wrong.

Compare this to different cars and trucks from the ’70s or, even better, the ’50s and ’60s, that don’t have one single vulnerable piece of gear on them. Maybe, maybe, a mechanical coil pack could be damaged or destroyed, but by all accounts, even this is uncertain.

Bottom Line: The age of your vehicle, broadly speaking, directly influences its EMP vulnerability. There is an awful lot to go wrong on new cars, and not nearly as much on older vehicles that are more EMP-proof, so to say.

Most Modern Vehicles Might Be More Trouble Than They’re Worth

Consider that if you have a very new car, there might be so much going wrong with it in the aftermath of an EMP that a repair is just not feasible, even if you have the parts on hand, the tools, and the skills to do so.

You might be wrenching on your car so long and running down so much wiring and data lines that the thing is effectively totaled.

Think carefully before you commit to getting ready for the aftermath with your vehicle, and consider getting an older but serviceable “beater” that’s more resistant to this kind of event if you have a very new car.

First Things First: Get a Paper Copy of Your Car’s Repair Manual

Unless you are already a technician with a lot of experience, or you work on your own vehicle and know it intimately inside and out, the very first thing you need to do is get a repair manual for your car.

Especially for us folks who aren’t wrench-turners by trade, this is going to save the day when you need to start pulling parts and changing out fried components.

Haynes is the standard for such manuals, readily available and affordable, so I recommend you get one for the model and year of whatever you drive. Keep it stashed in a safe place with all of your other survival necessities.

But before you do that, review it to get familiar with how big of a job it is to change out those vulnerable electronics we talked about above, and what tools you’ll need to do it.

Get a Malfunction Scanner and Learn How to Use It

Another invaluable item you should have handy for this job is a malfunction scanner. This is that little dongle that technicians plug into your car, typically somewhere under the dashboard or beneath the steering column, to get a code from the car’s computer that will tell them what’s wrong.

These things aren’t that expensive, and you can use them for the exact same purpose. Of course, there is a caveat here: there’s no guarantee that the car’s computer will even be functional under the circumstances, but it’s definitely worth a try.

At any rate, you can use this in the meantime when your car’s check engine light comes on to see what’s gone wrong and then attempt to fix it yourself. Consider this a homework assignment for building your post-EMP resiliency.

Have Spares on Hand for Likely Points of Failure

The trick with an EMP is that, when they are strong enough, they don’t simply disrupt electrical function; they can cause damage or even totally destroy vulnerable systems and components.

Accordingly, you need to have those spares on hand if you want any hope of getting your car back on the road. What spares should you get? It depends completely on your make and model of vehicle. There’s no true standard list for something like this. That’s why it is so important to get your hands dirty and do your homework using a repair manual.

For most cars that are made starting around the early 1980s or a little bit after, this should include some or all of the following components:

Transmission Control Modules (TCM)

The TCM operates a transmission, manages the torque converter, and optimizes performance through the adjustment of shift points. These devices rely increasingly on microprocessors and all sorts of circuits to work, and so are highly vulnerable to EMPs…

Engine Control Units (ECU)

The engine control unit, sometimes referred to as the electronic control unit or electronic control module (ECM), controls the majority of the vehicle’s electronic subsystems related to ignition timing, air intake, fuel injection, and more.

It relies on various sensors, detailed below, to do its job. If this gets knocked out, your engine might malfunction or fail to work at all.

Body Control Modules (BCM)

In more modern vehicles, the body control module is responsible for electronics relating to the interior and exterior of the automobile body, like lighting, windows, alarms, and other secondary or tertiary systems.

It might not be explicitly necessary for the engine and transmission to function, but if it is damaged or destroyed your vehicle might fail to operate normally or at all. Once again, check that manual!

Ignition Controllers

The ignition controller is directly responsible for the intensity and timing of the spark needed to ignite the fuel inside the engine. Depending on the make and model of the vehicle, this controller might be more or less susceptible to an EMP.

Ignition Coils

Coils, found in the coil pack, step up the low voltage from the battery to high voltage for igniting the fuel mix inside the engine cylinders.

These devices vary considerably in design, with older, straightforward mechanical coils being less likely to be impacted by an EMP. Modern vehicles use electronically controlled coil packs that are significantly more vulnerable.


This is part of the air conditioner and actually blows hot or cold air into the cabin. Again, not strictly needed for your engine and transmission to operate, but a malfunction might disrupt other systems in kind, so be aware of it.

Various Sensors

Cars use all kinds of sensors distributed throughout the engine and other systems – everything from temperature and airflow to pressure, speed, and more. These sensors will typically communicate with the ECU and sometimes other modules like the TCM.

Faulty sensors might subsequently interfere with these larger and more important components and result in malfunction or a failure to function.

Idle Air Control Motors

The IAC motor manages the idling speed of the engine, and if damaged or destroyed, might cause unpredictable idling speeds or unpreventable stalling.

Fuel Pumps

You probably already know what this part does! Fuel pumps send fuel from the tank to the engine at the necessary pressure. Pretty much all modern ones are electrically controlled.

High- and Low-Speed Data Lines

Don’t forget that the lines themselves going from various sensors to other control modules are themselves directly vulnerable to the high voltage of an EMP. It wouldn’t do to replace an affected component and leave it connected to damaged data lines!

Remember: if an EMP can affect the component and the component is mandatory for your car to work, you must have a good working spare in your possession.

Don’t Worry Over Non-Essential Systems

On the other hand, there are many vulnerable systems on cars that you can get away without having or even attempting to repair.

For instance, digital radios or CD players, electronic tire pressure sensors, and other such things aren’t needed to make the car “go,” and replacing them is strictly optional, or you can wait until life gets back to normal.

That said, it’s imperative that you really understand what can knock your car out…

Something like a multifunction display or instrument cluster might have some sort of failsafe built into it that prevents the car from operating or causes negative interactions with computers and so forth, causing malfunction or even total inoperability. Read that manual, folks!

Keep Your Spare Parts Shielded Until You Need Them

Having the spare parts on hand isn’t enough. If you just have them sitting in the garage or lying around, they might still be damaged or destroyed by the EMP that knocks out your car in the first place! Replacing a broken part with a broken part isn’t going to do you any good!

It might sound crazy, but it makes sense if you understand a little bit about EMP physics: an EMP is an electromagnetic wave, or pulse.

When it contacts conductive material, and particularly electronics, it actually energizes them of its own accord, no power source and no connection to the vehicle needed. For the most vulnerable systems like circuit boards and microchips, this can result in destruction.

For this reason, you must shield those components using a Faraday cage. A Faraday cage is nothing more than a conductive and fully enclosing envelope that can protect vulnerable parts from the effects of an EMP.

You can buy specially produced bags and boxes for the job, or just use something simple like an all-metal trash can with a lid on it. Just be sure to protect your spares if you want to depend on them.

Another thing you can do (if you’re up for the challenge) is to keep your vehicle in parked in a Faraday cage. It isn’t as crazy as you think, and it is possible to make your own if you have space and a little DIY ingenuity. Check out this article for more info.

Before You Start Wrenching: Try to Restart the Car!

One really important thing I need to share with you. If an EMP actually happens and your car shuts off or starts to malfunction, don’t go reaching for those spare parts and your tool bag just yet.

Turn off the car, wait a couple of minutes, then try to turn it back on. There is a precedent, based on testing done by government and private labs (including L-3 and White Sands), showing that some vehicles that wind up knocked out by an EMP may only be temporarily affected.

It’s a long story, and the actual results of the test were naturally affected by government and business interests and furthermore weren’t released to the public, but based on what we do know, it’s worth a try.

If the car doesn’t start again, next disconnect the battery and wait about 5 minutes before reconnecting it and then trying once more to restart the car. Sometimes removing the power source from the vehicle lets everything reset to its nominal state.

Only if these two measures fail should you then get down to the business of attempting diagnosis and parts replacement.

If Vehicle is Inoperative, Check for Codes and Start Replacing Parts Logically

Post-event, if your vehicle unfortunately fails to start, then it’s time to start checking for codes. Plug in your code scanner and see if you can get any codes from the computer.

If so, proceed with the fix and then rescan. If it doesn’t work at all or if the computer itself is fried, you’ll have to rely on your manual.

As a rule of thumb, if your car has an ECU, test and replace the ECU before you do anything else, then proceed logically replacing vital components according to their importance and also how easy they are to reach.

The idea is that you should change out the most important parts that are most likely to sideline your vehicle. Nominally, you should also change them out according to how easy they are to get to, saving the most laborious or difficult for last.

The Better You Know Your Vehicle, the Easier the Job Will Be!

As with all things prepping, hands-on experience makes for light and quick work, and will also save you stress during what is already a scary situation.

You should endeavor to start working on your own vehicle now while times are kind so you can start getting experience.

Do basic maintenance, diagnose it when there’s a problem, and change the part out as you can, accumulating the needed tools slowly and organically if you don’t already have a collection.

This way, when you need to do your own post-EMP repairs, you’ll have the confidence to do it right and quickly the first time.

repairing car post-EMP

4 thoughts on “How to Get Your Car Working Again Post-EMP”

  1. The fuel you have on hand will be all you will have. No gas stations will be open, and everyone else will hoard theirs. Then … over time … all the fuel will go bad. Also, If you can drive, drive frugally. Oh, and make sure the vehicle makes no noise … or others will be tempted to kill you for it. Fun times.

  2. I have a question about EMPs. How big of an area does a EMP strike effect, would one incircle the entire Earth? Or is it only the area that’s in sunlight? Can an EMP strike at night time?

  3. I have 2 vehicles.
    My daily commuter car, a 2020 Honda Fit. Gets 38 mpg, isn’t fancy or sporty, but it gets me to work and back. I doesn’t have all the computerized crap, GPS, ApplePlay, or anything like that. It does have a nice AM/FM/MP3 radio with a back-up camera. In an EMP…this car is toast. I know it and the car probably knows it. LOL
    My Weekend vehicle is a 1966 Dodge D100. Ok, so it ain’t the best looking truck. You don’t see many on the road. But I have all types of parts for it. It’s easy to work on. Gets me to the hardware store, gets my Kayak to where I want to fish. Has an AM radio and a CB. After an EMP…this truck will still be going.

  4. WE have so many smart people that can invent. we need a retrofit ignition system that would replace and provide the spark with timing to run even for low speed. It is a good plan to make some money from preppers.—— I, Grampa

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