Skip the auto shop - Our mechanics make house calls

What Is a Reprogrammable ECU?

electrical control unit

The ECU, or engine control unit, is part of your car’s computerized brain and is responsible for monitoring and managing all aspects of engine operation. For anyone who isn’t interested in upgrading their car for higher performance, the stock ECU is all that will be needed. However, if you’re contemplating building a high-performance machine, you’ll need a reprogrammable ECU that can be flashed to change your engine’s performance.

Stock ECUs

Your car comes with an unalterable ECU (with some very minor exceptions). It runs on software that can sometimes be upgraded, but only to a better version of the automaker’s software, and then only rarely. Sometimes you can “tweak” stock settings, but that’s also limited. These come preset from the factory for your car’s engine as it was when it was built. If you’ve made modifications to the engine designed to boost power, there’s a chance that the stock ECU won’t cut it. Most ECUs are not programmable/reprogrammable. However, there are aftermarket options that can be reprogrammed.

Aftermarket reprogrammable ECUs

Aftermarket programmable ECUs replace your stock computer with an aftermarket computer. These are designed to let you adjust pretty much any setting you want for the engine, from ignition control to controlling intercoolers and more.

Making adjustments to a reprogrammable ECU is generally simple – you connect the ECU to a computer loaded with the right software. The engine controls and settings are displayed through this software, and they can be adjusted with a mouse or a keyboard. However, it’s vital that only a thoroughly trained professional adjust your engine settings. If you’re not entirely sure what you’re doing, it can be very easy to throw off the entire engine.

Do you need a reprogrammable ECU?

Chances are good that you don’t need a reprogrammable ECU unless you’re doing serious modifications to your car’s engine for better power and performance. In this instance, even programmable stock ECUs won’t offer the unlimited access to systems and settings needed to achieve the level of performance you want.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
Icon-warranty_badge-02

Skip the repair shop, our top-rated mechanics come to you.

At your home or office

Choose from 600+ repair, maintenance & diagnostic services. Our top-rated mechanics bring all parts & tools to your location.

Fair & transparent pricing

See labor & parts costs upfront, so you can book with confidence.

12-month, 12,000-mile warranty

Our services are backed by a 12-month, 12,000-mile warranty for your peace of mind.

Get A Quote

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.

GET A QUOTE

Post a question and get free advice from our certified mechanics.

ASK A QUESTION

More related articles

P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the P0052 code means This code is seen when the Engine Control Module (ECM) tries to control the...
P0222 OBD-II Trouble Code: Throttle/Pedal Position Switch/Sensor B Circuit Low Input
P0222 code definition Throttle/Pedal Position Switch/Sensor B Circuit Low Input What the P0222 code means The manufacturer specifies a range of acceptable voltage to be produced from the throttle position...
P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...


Related questions

Q: Automatic seatbelt on drivers side stuck in open position

The seat belt track needs to be replaced most likely. The track works like a window motor and it requires the door to be closed completely to operate. Once the door is verified to be closed and signal to belt...

Q: Car service required

Hello. I just took I look at the maintenance table for your Chevrolet Spark and there are few think that are suggested at 55000 miles. Inspect the transmission fluid, inspect the engine's air and cabin air filter, engine oil change,...

Q: Hello, my car has no spark, no controlled ground for the fuel pump, and no injector pulse. Fuse link close to the battery and relays are good.

Hello and thank you for contacting YourMechanic. The ECU is under your passenger's side seat. You can gain access to it by simply sliding the seat all the way forward and removing the plastic cover from the ECU. You can...