Car acting like battery disconnected after parking
 

Hey everyone, I had an extremely odd thing happen to my '12 86 today.



I pulled up into a car park, got out and It wouldn't lock from the key remote. It also wouldn't unlock/flash indicators etc.i just thought the key was dead - but the little red light in it was turning in? So I then tried to the lock switch by the window switches, and it didn't work. So I thought maybe the ignition had to be on for the switch to work, and to my surprise nothing turned on when I turned the key, no dash lights - nothing. But then... All of a sudden everything came back on? Like it was just acting up for some reason?



All the symptoms of a battery terminal being disconnected are present - the radio memory reset for example, and the throttle calibration has been forgotten/needs to relearn again. It also now seems super inconsistent with the throttle - it stalled almost every time returning to idle after releasing the throttle, but would drive 100% normally otherwise. I have disconnected the battery many times and it would never stall itself after the throttle is trying to re-learn, although I admit maybe I didn't give it enough time before I started driving.



I of course checked the battery and nothing seems out of place. The terminals are tight, there are no obvious loose wires anywhere or anything like that. I have no idea what went wrong or where to start looking for issues, anybody hear of anything like this before? How could the electronics like just disconnect and reconnect themselves like that?

After a decade or so, it's possible for corrosion to be a problem in various electrical connectors.
Under the hood, dash, seats, trunk - there's tons of them. Chasing which one can be frustrating.
I've had it on a motorcycle where they route through the headlight to the ignition key.

Usually re-plugging works short term, but doesn't keep the existing corrosion from progressing again.
Giving the pins/plugs a light coating of di-electric grease will slow it down by keeping free ions in the air isolated.

The ECU/BCU/TCU modules would be the places to start.

No guarantees. Some are convinced it could be juju too.

time to start checking fuses, as well as any modifications made to the car. especially the fuses on the top of the battery.

Have you taken off and cleaned the battery terminals?

Have you load tested the battery?

hmm good idea I'll check them all soon. Didn't think about the battery terminal fuses, I'll check them too thanks.

I haven't taken them off, no. Nor have I load tested it, but the engine starts completely normally and voltage levels both 12v and 14v are all normal. I'll try that though if nothing else comes up, but I don't feel that they'd be 'bad' enough to cause this issue.

Welp, battery terminals don't have to look this bad for them not to make consistent contact - ;)