Hi,
Just change to a new car battery on my Lanos SOHC. The battery guy insert a power plug into my cigarette lighter hole. The other end of the cable was a box with indicators. I asked him what is he is doing. He said that this is to record the setting of the ECU before remove the old battery.
Could anyone advise me what is ECU ? What is the role of ECU ? Can we do the setting of the ECU by ourselves ?
Thanks.
Regards,
Koh
Reset ECU After Battery Change
Moderators: daewoomofo, Moderators Group
what you saw is very strange... their is no way in hell to record ECU readings through a cigarette lighter hole unless their was another cable that you didn't see that was hooked to the OBD socket... even then he can't really "record" the ECU readings it will be just a "monitoring" job and it is totally usless for a battry change job anyways.
an ECU is the Engine Control Unit (AKA PCM) and it is simply the brains that manages how your engine works among other things like ABS and airbags and stuff like that but basicly it is managing the engine functionality.
you can't set the ECU yourself as it is programmed by the car manufacturer so you can't do anything about it. the only thing you can consider as "setting" is the learning procedure.
the ECU starts to learn all the feedback from the various sensors on the car and records this data to optimize the engine performance... some times when parts get old, dirty and get replaced on regular maintenance jobs or you do a performance upgrade or so the ECU's stored data are not that accurate and compatable with the changes you recently did so the engine misbehaves.
you can simply unplug the -ve battry cable for a few minuts to reset the ECU (clear its learned data) and put every thing back and start the engine and follow the correct learning procedure to correct this problem... in this case you didn't change the ECU's progrtamming, you just wiped out its stored feedback on your engine and as soon as the learning procedure is over this data will be built up again in a correct way.
refer to the how to section concerning ECU resetting and learning procedure jobs.
also an OBD sockeit is a socket used to hook the ECU to an On Board Diagnostic tool... this tool reads out all the sensors through the ECU and shows if something is wrong... no programming is possible through this either, it is just a read out port. this socket is located under the dash board on the right side or right next to the gas pedal depending on which year your car was made.
in case you got a CEL (Check Engine Light) you have to scan the car by using the OBD scan tool, the tool can detect the DTC (Diagnoistic Trouble Code) and you can know whats wrong wioth your engine depending on the code you got.
knowing all that you can see that simply pluging any device to the cigarette lighter hole can't read anything from the ECU unless their was another socket going to the OBD socket, also reading the ECU for a battry change job is not necessary at all... i have no idea why the guy did that.
MMamdouh
an ECU is the Engine Control Unit (AKA PCM) and it is simply the brains that manages how your engine works among other things like ABS and airbags and stuff like that but basicly it is managing the engine functionality.
you can't set the ECU yourself as it is programmed by the car manufacturer so you can't do anything about it. the only thing you can consider as "setting" is the learning procedure.
the ECU starts to learn all the feedback from the various sensors on the car and records this data to optimize the engine performance... some times when parts get old, dirty and get replaced on regular maintenance jobs or you do a performance upgrade or so the ECU's stored data are not that accurate and compatable with the changes you recently did so the engine misbehaves.
you can simply unplug the -ve battry cable for a few minuts to reset the ECU (clear its learned data) and put every thing back and start the engine and follow the correct learning procedure to correct this problem... in this case you didn't change the ECU's progrtamming, you just wiped out its stored feedback on your engine and as soon as the learning procedure is over this data will be built up again in a correct way.
refer to the how to section concerning ECU resetting and learning procedure jobs.
also an OBD sockeit is a socket used to hook the ECU to an On Board Diagnostic tool... this tool reads out all the sensors through the ECU and shows if something is wrong... no programming is possible through this either, it is just a read out port. this socket is located under the dash board on the right side or right next to the gas pedal depending on which year your car was made.
in case you got a CEL (Check Engine Light) you have to scan the car by using the OBD scan tool, the tool can detect the DTC (Diagnoistic Trouble Code) and you can know whats wrong wioth your engine depending on the code you got.
knowing all that you can see that simply pluging any device to the cigarette lighter hole can't read anything from the ECU unless their was another socket going to the OBD socket, also reading the ECU for a battry change job is not necessary at all... i have no idea why the guy did that.
MMamdouh
Driving is the utmost fun you can have with your pants on!
Check out my ride: http://www.cardomain.com/ride/567267
Check out my ride: http://www.cardomain.com/ride/567267
What they probably did was put a 12 volt battery in your lighter socket, so that your ECU (main computer,) keeps all it's settings. This is good to do so that your car doesn't need to relearn all the nest settings for optimal efficiency. If they didn't do that, you would have lost everything when they disconected the main battery. I have one of these devices myself, because I hate having to put all my radio stations back in when I have to take out the battery.
My Chevy Woo
2004 Chevy Optra 5
2004 Chevy Optra 5
sounds like a good idea 
MMamdouh
MMamdouh
Driving is the utmost fun you can have with your pants on!
Check out my ride: http://www.cardomain.com/ride/567267
Check out my ride: http://www.cardomain.com/ride/567267