What is an ECU?

Question

What exactly is an ECU in a car, and how would you go about resetting one?

Also what is it's purpose/what does it do exactly?

I think it stands for Electronic Control Unit?

Answer 1

It does stand for "Electronic Control Unit".

There can be more than 20 of them in a modern car, but the key one (and the one more often referred to as the ECU) is the one that controls the engine. It contains software that uses inputs from engine sensors, exhaust emission sensors, temperature sensors and a throttle-pedal position sensor to control the amount of fuel injected, the injection timing, the ignition timing (in a petrol engine), and any other features the engine may have such as an electronically controlled throttle, variable valve timing/lift or exhaust-gas recirculation.
Re-setting it may be as simple as disconnecting it for a while, or it may require using a lap-top and specialist software to completely reprogramme it.

Answer 2

ECU = Electronic Control Unit
Engine Control Unit
Same thing, everyone else is saying. Here's my addition to the info given. Modern cars have learning software built in to the ECU. What it does is it learns how the driver drives the car. Some higher end cars can do this for multiple drivers. Have you seen the Driver 1 / Driver 2 buttons? They change the pedals and seats for the drivers. Well, they also change how the ECU manages the performance of the engine. If you like to "take off" at the green lights, it will deliver the fuel appropriate that style of driving, however, if you are a sunday driver, it will handle that. If you reset the ECU, all previous learned perameters will also be erased and your car may run "funny" for a couple of weeks while it learns the way you drive and makes the nessessary adjustments.

Also, someone else posted about losing stereo presets. This is also true. Your stereo may also think it was removed and reinstalled, so you may need to enter the unlock code to use it. If you don't know it, you will need to either send it in and have it unlocked by the manufacturer for a few hundred dollars, or just replace it. Good luck!

Answer 3

hope this ite will help u!!!!!!!!!
http://www.tundrasolutions.com/forums/engine-and-drivetrain/54203-how-exactly-does-the-ecu-work/

To "reset" the ECU, all you have to do is remove the source of backup power. To keep the memory alive while the car is off, the ECU has a direct line, through a fuse, that goes right to the battery. This is usually the same line and fuse that supplies backup power to your radio so it doesn't forget all of its settings. Your ECU has now lost all of its long term memory values and will "reset" them all to defaults when it next powers on. By the way, the factory radio's memory lasts for a minute or two, so you probably will not lose your saved stations.
Myth

There is quite a bit of mythology revolving around resetting the ECU. Many people mistakenly believe that they need to reset the ECU after installing major engine modifications. Others believe resetting will resolve engine problems. Neither are correct.
Reality

The ECU is always tracking the engine's sensors and actuators. Resetting the ECU does not cause the ECU to learn engine changes any faster. The ECU is always tracking the gradual changes in the engine sensors and actuators. The ECU never gets satisfied with a setting, and is always updating the trim values. It will discover whatever change you made to your engine and make the appropriate changes. In fact, unplugging the ECU will most likely increase the learning curve of the new part.
There are only two reasons why you would want to reset your ECU. One is to clear a CHECK ENGINE light or error code after fixing the problem that caused the error. The other is to reset the spark advance trim value. The advance trim controls how much the timing is retarded from what the factory engineers considered optimum. This particular trim value is the only one the ECU "resets" to a non-neutral MAX value. If you are driving on low grade gas, the pinging picked up by the knock sensor causes this trim value to be lowered, and your timing to be retarded. If you go to the track and put good gas in the tank, you might not want to wait for the ECU to learn about the new gas and advance the timing. So resetting the ECU in this case makes sense. However, in the process, you will lose your idle and fuel trims (probably not too important for drag racing, though).

Answer 4

ECU generally stands for Electronic Control Unit as has already been mentioned. It is sometimes also known as Engine Control Unit, but both terms mean the same thing. You can usually reset the ECU on any car by disconnection the battery for about 20 minutes, but you will loose the radio presets if you do. It is a better choice to use diagnostic tools to do this. Be aware that many entertainment systems will forget what their purpose in life is, if you do not have the reset codes when the battery is reconnected.

Answer 5

The Electronic Control Unit is a computer unsed in most cars made sine the late 80's. It continuously responds to electronic sensors to keep the engine running as efficiently as possible. This reduces pollution and improved fuel efficiency. The most Basic ECU controls only the ignition. some like the Ford EEC-IV and EEC-V control the ignition, injection, and transmission.

New cars use a standardize ECU, the OBD-II system. OBD-II system started showing up around 1993. Most pre OBD-II systems can be reset by disconnecting the battery cables and grounding the positive cable for about 15 minutes. OBD-II systems must be reset with a compatible scan tool. Most autoparts stores sell the scan tools.

Answer 6

This Site Might Help You.

RE:
What is an ECU?
What exactly is an ECU in a car, and how would you go about resetting one?

Answer 7

An ECU stands for Electronic Control Unit. It controls the engine in terms of fuel mixture, transmission shifts and cruise control. If your car is an older car (80's to 95) than all you need to do to reset the computer is simply disconnect the battery cable and the cars computer will loose its memory.New er cars (96 to present) you will need to go to your mechanic to have them reset the computer because newer cars have memory chips rather than flash memory so the cars computer will store trouble codes and keep them until the problem is fixed or the computer is reset. If the engine light is on in your car than you need to get the problem fixed simply resetting the computer will only temporarily make the check engine light go out. Sooner or later the computer will detect the problem again and it will set another trouble code.

Answer 8

Newer cars have multiple ecu's. They control abs, air bag, electronic temp control, lighting, etc etc. I think you mean pcm, or powertrain control module. This module controls the functions of the engine, and sometimes the trans as well. Usually unhooking the battery for 5 min will reset the pcm.
It works by monitoring various engine inputs via sensors, then compares that data with a pre-programmed set of data, and makes the appropriate changes through output controls, such as injectors and ign. timing.

Answer 9

an ecu is an electronic control unit which controls fuel and air mixture as well as the injectors cold start (auto choke) To reset one you need to go to either a garage wich has all the relevent computer software to plug into the engine management system or have the software yourself and know what the hell you are doing

Answer 10

yeah elec cont unit
jags have around 400
they control everything like windows, fuel inject, elec seats etc
to reset you need equip that costs more than ecu

xxx