Skip the auto shop - Our mechanics make house calls

Q: Does a new ECM for this year make model need to be flashed in order to drive the vehicle? 2004 Ford Focus

asked by on

Considering purchasing a 2004 ford focus with a bad ECM. Id like to replace the ECM but id like to know if I need flash the ECM in order to drive the vehicle. If so, what side effects will I have from driving this car with an unflashed ECM.

My car has 179000 miles.
My car has an automatic transmission.

A: Yes, a new ECM will have to flashed before ...

Yes, a new ECM will have to flashed before you can even start your vehicle. The "flashing" or programming of the ECM will require your VIN number to the supplier, who should be updating the most current software for your specific vehicle. Otherwise, you would have to tow the vehicle and the new ECM to a Ford dealer for this service. Make sure your parts supplier has the capability of doing this before selecting them so your replacement will not leave your stranded.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Save up to 30%

Get a quote

What others are asking

Q: I got my idle control valve and throttle position replaced a couple days ago, but now my car stalls.

Hello. It is possible that the part is defective, but most of the time this is because the computer has to relearn the new idle control valve. Sometimes, this can take a little while before it works correctly. It is...

Q: Truck lacks power and won't accelerate but isn't throwing any codes

Quick checks would include transmission fluid level, be sure the tranny isn't stuck in 2nd gear (limp mode), the brakes aren't dragging, or one or more wheel bearings are rough, clean air and fuel filters. Beyond that, if there are...

Q: Seems like a belt squeal upon cold start and gets louder with acceleration. Stops after the car is warmed.

This may be related to a squeaky belt. In cold weather these belts will make this kind of squeal when the rubber belt material is cold. The cold weather causes rubber to be less pliable and a bit brittle. As...

Related articles

What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...