ECU reset

I was removing my ECU to have it re-flashed. First I unplugged it, then removed all the screws. While removing the screws (a 90 min. process) my interior lights went out. I plugged the ECU in and tried to start the car and everything worked just fine and the engine would crank; it just wouldn't turn over or actually start.
I realized that I didn't disconnect the battery before plugging or unplugging the ECU, but I checked an I didn't smell anything burnt. A friend told me that when I re-install it, to disconnect the battery terminals for over a minute and re-attach them and it may reset.
Are there any other ideas out there? I need other possibilities because I won't be able to wait too long to try this mod out.

what kind of car is it?

I thought that most often the ecu is grounded to the car. Soooo you may have shorted something inside the ecu or elsewhere. Probably in the ecu since everything non computer controlled works you said. I dunno, you'd have to do a bit of troubleshooting.

Also, the reset won't matter since you've taken the ecu out to be reflashed. The ecu is out of the car right? If that's the case then hopefully it'll work when you plug it in, if not, then something is fried.

It's a 2003 Nissan Maxima. Yeah, the ecu is out of the car now, but I was talking about disconnecting the battery when I plug it back in.

It doesnt matter. It's been disconnected from the car now, so it'll be 'reset' by the time you plug it back in.

What the hell are you talking about really? Do you mean hook up the computer, then do a reset by unplugging the battery?
Or, should you have the battery unplugged when you put the ecu back in?

Of course you should unplug the battery before plugging or unplugging the ecu....

you wouldn't smell anything burning because it didn't short long enough for anything to burn. I'd say the problem is something shorted inside the ecu when you either plugged it in or unplugged it, you're going to need a new one.

you always remove the power source before you do anythig electrical, doesn't matter what it is you HAVE to remove it before doing ANYTHING. with these small electical circuits it doesn't take much to completely mess them up, you probably made a spark jump where it wasn't supposed to jump, or didn't touch all the pins at the exact same time so something got too much current for a fraction of a second and fried. you have no idea how small the wires in there are, literally smaller than a hair, and it doesn't take much for them to melt. i guess you learned a tough lesson, next time i hope you'll remember. it sucks but it's probably going to be an expensive mistake.

I thought that most often the ecu is grounded to the car.
if you're refering to the body of the computer being grounded through the chasis contact, nobody has done that in eons. All grounds are through the harness. Or I should say, the body of the ECU's primary ground source is through the harness.

if you're refering to the body of the computer being grounded through the chasis contact, nobody has done that in eons. All grounds are through the harness. Or I should say, the body of the ECU's primary ground source is through the harness.

I thought about that after I wrote that, but I didn't really care to edit it. lol

I just disconnected the battery when I put it back in. Now my sunroof and fog lights work intermittently though. I can live with that. Everything else works normal.

The upgrade was awesome though.

I just disconnected the battery when I put it back in. Now my sunroof and fog lights work intermittently though. I can live with that. Everything else works normal.

The upgrade was awesome though.

2 things that are completely independent of the ecu. Good thing you didnt fry the computer.

The ECU can be fitted and removed without disconnecting the battery, so, no worries there. However, before you replace the ECU ground yourself by touching the car and do not touch the connectors on the ECU. Make also sure that you fit the ECU correctly.

When a new ECU is fitted to the car, they usually need to get "married" with the car to work.

2 things that are completely independent of the ecu. Good thing you didnt fry the computer.

Usually these functions are controlled though a another electronic control unit, and when the power is lost, these may have lost their settings. These days almost everything in a car is controlled by a computer.

Everything works fine now. Guess things just had to reset themselves.