3rdwheel

I am wondering if someone can tell me, if the battery has been disconected, will it reset the ecu so when a new battery is installed, any old codes would be lost? I am trying to avoid any excess troubleshooting. Thanks

ezone

Disconnecting the battery erases most codes.

HTH

3rdwheel

Do you know what needs to occur before the ecu starts to show error codes again?

ezone

A fault needs to be detected.

It doesn't have ESP.

3rdwheel

Yes indeed, but I was not clear. If a problem exsists and the ecu has been reset will it read the old problem, if one exsisted before it was reset.

MindBomber

If the fault that triggered the code prior to the reset has not been corrected, then it will detect that fault and activate the code again.

ezone

If a problem exists and the ecu has been reset it will read the old problem.

3rdwheel

Thanks for that. I am still wondering will the ecu show codes as soon as the battery is reconnected or does something else need to happen, like the car has to be running, the key has to have been turned on 100 times, etc, before will show codes again. In case you could not tell, this is a learning experence for me.

MindBomber

The ECU needs to detect the fault again for the code to be activated.

In order for the ECU to detect a fault, a fault must occur.

A fault is not predictable, it may occur the first time the engine reaches operating temperature post reset or after several hours of driving if not longer.

3rdwheel

Well the 90' civic si is Resurected! After sitting for 5+ years, I followed the steps outlined by ezone (months ago) and started troubleshooting the electrical. I resoldered the s**t out of the main relay, put some oil in the plug holes and started cranking. Took a little while, but she finally built up enough compression to catch. Sure did blow some smoke! but by the end of the drive (15mi or so) she was sounding real smooth. Got a Nasty high speed shimmy, tires are toast I am guessing. Still no ecu codes, guess I will wait and see about that. looking forward to driving this Fun and economical rig again!