Some and I should say most when buying second hand you have to have what they call a security kit, this means that you must get a ECU/ECM, a BCM (body control module), key and ignition, key reader, and some even the instrument cluster for these second hand units to work, and you must match your existing ECU/ECM numbers ...
Each car has its own specific ECU that has been designed, calibrated and mapped for that engine. ECUs aren't interchangeable, and if you require a replacement, you should use an OEM part.
If you mean can a bad ECU be replaced with a used one from a similar vehicle, yes.
The engine control module (ECM) is the computer that manages every system on the vehicle related to emissions. When something goes wrong, the ECM will hopefully record a diagnostic trouble code and turn on the check engine light. But the ECM (all by itself) can do nothing. It first must be programmed.
Whilst you can adjust and replace the ECU in a vehicle that is predates 2001, you may have difficulty with newer cars. Many of these have complex computer systems and you will have to take them into an authorised dealer to have reconfiguration work performed under the hood.
In general, yes. All ECUs will need to have software intended to run the engine it is connected to. In addition, many newer cars (approximately 2008 or newer) use a CAN bus system where each component (like the ECM, BCM, PCM, etc) all need to be programmed to the VIN number of the car to work properly.
Can I program my own ECU? Yes, of course! ECU is an important part of a car. It controls the function of various systems such as fuel injection, ignition timing and emissions control.
The replacement of the ECU depends on the model of the car. Older ECUS could be replaced without programming as security features were less. But modern cars have high security features including recognition of keys, thumb impression, odo meter readings and hence would need reprogramming.
ECM Parameters
Engine parameters may include fuel injection volume, throttle-fuel volume mapping, gear shift mapping, and so forth. Because these limits are tailored to your specific vehicle and engine, you can't just swap out one ECM for another without also updating or modifying the software.
What Do ECM and ECU Stand For? ECM stands for Engine Control Module, and ECU is short for Engine Control Unit. These two acronyms represent the same component and are used interchangeably.
These typically cost somewhere in the ballpark of $200-$400. Again, the actual cost of repairing and replacing the ECM will depend on the make and model of your car. If the engine control module just needs to be tested, analyzed, and reprogrammed, it should cost you between $150 and $300.
The spark plugs and their coils tend to be regular maintenance with the age and mileage of the vehicle. The engine control unit is a component that can last the lifetime of the vehicle, or develop issues after 100,000 miles.
If the original ECU is suspected of malfunctioning or causing problems with the engine, it may be useful to clone the original ECU onto a replacement unit that is known to be in good working condition. This can help to eliminate any issues caused by the original ECU and ensure that the engine is running properly.
Check the symptoms
These may include poor engine performance, stalling, misfiring, rough idling, poor fuel economy, check engine light, or no start condition. Some of these symptoms may also indicate other issues, such as faulty sensors, wiring, or spark plugs, so you need to rule them out before blaming the ECU.
If there is physical damage on your ECU, then you will have to have the ECU replaced. The cost of replacing a ECU can be a few hundred pounds if you drive a very basic car, or well over a thousand pounds if you drive a premium model.
If you are just wanting to implement some slight modifications like exhaust and air intake, then you will most likely be able to tune and program your existing stock ECM to meet your needs. On the other hand, if you are trying to convert your vehicle into a race car, then you will most likely want an aftermarket unit.
Cost of ECU Tuning
New tires, repairs, and yes, even ECU tuning vary in cost, too. On the extreme low end, an ECU flashing could cost around $300, but it can go as high as $3,000. Flashing kits are available for a few hundred dollars, and some people do ECU tuning as a sort of hobby or side business.
You can tell as flashed car by driving it, also the boost is around 1 bar as opposed to . 6 - . 7 for a non flashed car. If you have access to a PIWIS or PST2, it will show that the ECU had been "altered".
The ECM will usually last the lifetime of the car, though it can go bad. In fact, the computer can fail as early as 75,000 miles, and around 125,000 miles is the most common range for ECM replacement.
The easiest way to perform an ECU reset is by removing the fuse from the fuse box. It is a very simple process, and all you have to do is pull out the car key, remove the fuse from the fuse box, and then put it back after about 15 to 20 seconds. Doing this clears any long-term memory stored in the car's ECU.
In many cars, the ECU stores the mileage. In other cases, the body control module (BCM) stores the information. In some newer vehicles, you may not need to do anything. The mileage will automatically show up on the new instrument cluster when you install it.
PlugIn ECU's, often referred to as Plug'n'Play units, are a direct replacement for the factory unit in your car. No additional wiring is needed when installing a PlugIn, nor an adapter harness.