How Do Aftermarket Tuner Chips Affect Your Car?

Modified software can boost output — or cause a lot of problems.

Sebastian Blanco | 

Feb 15, 2024 | 3 min read

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An aftermarket tuner "chip" or program — also known as an ECU (Electronic/Engine Control Unit) reflash — is the kind of upgrade you can often do yourself if you're experienced. As well, a certified mechanic can install an aftermarket tuner in your car if you prefer. Computerized engine management upgrades can improve certain aspects of vehicle performance — be it in power output, fuel economy, or some other driving characteristic. Upgraded ECU tuning software works only on vehicles with computer-controlled powertrains, however, and these reflashes range in price.

Installation can be as simple as connecting a device to your car's OBD-II port. Most often it doesn't even involve a physical chip, just new software for the powertrain control unit. Chipping a car can cause serious problems, though, so here are a few considerations to keep in mind.

How Does a Tuner Chip Work?

Modern vehicles use computers to control myriad systems in the car, including fuel injection, ignition timing, transmission shifting, various suspension settings, and more. The automaker has already determined how these systems should run to achieve the optimal balance of performance and fuel efficiency while keeping wear to a minimum. Tuner chips, however, affect these parameters to meet a desired effect.

For example, a chip may adjust an engine's fuel-injection rate, which could change the air-fuel mixture to create larger explosions in the cylinders and produce more horsepower or torque. New ECU software may also advance the ignition timing to increase engine output. Some chips tell the transmission to shift sooner or hold gears longer, improving fuel economy or response. Others may take advantage of a higher-octane gasoline to boost performance.

Can a Tuner Chip Cause Damage?

While many retailers may say such chips are harmless, that's not always the case. Chips can cause a car's powertrain, suspension, and/or other components to function in unsanctioned ways, causing excess wear and even costly damage. For instance, an aftermarket software tune could permit a rise in turbocharger pressure that exceeds the engine's safe operating range and thus could damage the powertrain.

Rewriting the engine's fuel-injection instructions can potentially lead to engine knocking — that is, a pinging sound that arises when fuel isn't burning properly in the cylinder. If left untreated, it can damage an engine's internal components at exorbitant cost.

Other Unintended Impacts

It is the owner's responsibility to ensure installing a performance chip does not void the vehicle's warranty. Some chips will disable certain emissions-regulation systems on your vehicle, which could cause it to fail a state inspection. And if the chip enables a performance boost with higher-octane gas, realize that you'll have to pay more for fuel.

There are countless stories of scammers selling bogus racing chips, so when considering installing one in your car, it's ideal to proceed with caution.

Sebastian Blanco

Sebastian Blanco has been writing about electric vehicles, hybrids, and hydrogen cars since 2006. His first green-car media event was the launch of the first Tesla Roadster in 2006, an event where he almost elbowed Arnold Schwarzenegger in the groin. Since then, he has been tracking the shift away from gasoline-powered vehicles and discovering the new technology's importance not just for the auto industry, but for the world as a whole.