Battery disconnect vs computers

[Darius]

In more modern cars with computers managing engines and transmissions how much risk of losing data is there if you have a battery disconnect and leave it disconnected for long periods of time?????

 

[Moparsmitty]

I've pulled newer cars into the shop that haven't been running for a long time, stuck a new battery in them and got them running without too much trouble. A lot of the time people stopped driving the car because it had something else wrong with it so we had to figure that out. Usually everything will reset back to factory settings. Also it will reset trouble codes but you can be sure that they will come back. The computers (PCMs etc.) won't lose their factory settings just because they've been without power. A lot of newer cars learn how you drive over a period of time and adjust the car according to your driving habits. If you disconnect and reconnect the battery, the car may drive a little differently until it relearns your driving style.

 

[Cranky]

You can hook up a maintainer to the car if you are worried about radio presets etc.....

 

[65-440]

none at all ... like moparsmitty said, it will relearn all of the adaptives after a short drive .. some cases I've had to hold the throttle open a bit to keep it running until the computer starts to learn, mostly on older systems though

 

[747mopar]

Don't know much about the computers but I put a wire directly from my battery to the stereo on my car so I can kill the battery without loosing memory, you could do the same.

 

[Darius]

Don't know much about the computers but I put a wire directly from my battery to the stereo on my car so I can kill the battery without loosing memory, you could do the same.

So how does that work???? You just keep the radio powered up AFTER you disconnect? Are you thinking to have a constant supply to the computer after the disconnect to the rest of the system?

 

[440beep]

I store my 98 Volvo for six months of the year and remove the battery while in storage. When I take Volvo out of storage there's a "set up drive" I have to do in order to get the onboard monitoring systems in the "ready" mode. I have an OBD II scan tool that allows me to see when the car is in the "ready" mode. Its my understanding that each car brand has it's own uniquie "set up drive" protocols.

Example: drive car at 2,500 RPMs for 6 minutes. stop. Then drive car at 2,500 RPMs for 8 minutes. stop. Drive car at 3,000 RPMs for 7 minutes. stop.

I've never lost my radio presets in the 6 months of no power and also have a tuned ECU and electronic boost controller which have not been affected either.

 

[Speedbird]

I've been disconnecting the battery on an infrequently driven 2005 Honda to keep a maintainer on the battery.
I'm worried about doing something bad to the car's electronics with the car in the circuit.
Everything works fine when I hook the battery back up.
What about that? Do you think it will hurt the car's computer if I leave the battery connected?

 

[idrivemopar]

Onlyone, I use a maintainer on my 06 GTO over the winter, and I leave the battery in the car and connected, been doing it for 9 years and never a problem with the electronics.

 

[440roadrunner]

So how does that work???? You just keep the radio powered up AFTER you disconnect? Are you thinking to have a constant supply to the computer after the disconnect to the rest of the system?

Many stereo systems have a separate "keep alive" wire to keep the memory intact