ECU question

[B K]

Can someone in the know tell what you lose, if anything, when you disconnect the chassis battery?

Thanks

[B K]

Can someone in the know tell what you lose, if anything, when you disconnect the chassis battery?

Thanks

[bruceh]

I think that question #1 is 'for how long?'

I have had mine off for varying periods and had no problem. The CD changer will lose its place and since I don't have any radio presets don't know if they go away or not. The automatic step works off the engine battery so it won't work as long as you are disconnected.

For longer periods, the drive computer(s) start to forget stuff. When I hade my engine replaced, the battery had been disconnected for about a week. When we first started to drive, it stumbled a bit. The tech riding with us said that the computer had to relearn its settings.

[Bigdaddy]

One thing that you can do to get rid of the stumble is turn the key to run, let all the panel lights go off, depress the gas pedal slow (about 15 sec) to the floor, release slow (about 15 sec), then start. Then the 'puter will learn faster. I do this everytime I disconnect the battery on my rigs.

[B K]

Thanks for the answers. But how in the world did you figure that out??

[Bob (WA0MQE)]

I've removed my ECM at least three, or maybe four, times can't remember for sure over a 3 year period. Sent the ECM all the way out to Brazel's on the west coast via UPS and they shipped it back. Turn around about 4 or 5 days. Prior to removing it, as required, I disconnect the chassis battery. Left it disconnected for the 4 or 5 days and then re-installed the reprogrammed UltraPower ECM and connected the battery. Everything worked just fine. Never noticed any stumbling or any other problems. The ECM has a non-volatile memory so if you don't change anything, nothing should happen to it. When Brazel's reprograms it I'm sure this reset's everything it learned, but I sure didn't notice any difference, other then the improvements due to the latest UltraPower upgrade.

[JWatkins]

The previous owner of my rig had cut in a chassis battery isolator switch that he, and now I, used to prevent the small voltage drains from slowly causing the chassis battery to go flat during storage. There doesn't appear to be any issue as far as I am aware.
Joe

[Easyrider]

I remove all the batteries from our motorhome every winter for storage, from early November to mid April every season. We have never had any problems with the ecu, including no problems with our ultrapower upgrade. In the spring I put the batteries back in, turn the key, and it fires right up and away we go. Only thing I have to reprogram is the radios.