Caanon

1992 SC400.

A few months ago PS pump was rebuilt, alternator replaced, and also ECU rebuilt. Has been fine for a few months.

I haven't been the one driving the car, so I didn't hear about problems till after the car died, but apparently it would run rough/rev high on idle sometimes and fine other times over the last few days. And then it ended up with a dead battery.


So first night I replaced the battery, I ran it in the driveway and it seemed perfectly fine, measured the voltage at battery with the car running and it was like 14.5 volts.

Next day I drove to get gas, car seemed fine and smooth, got home and checked voltage while car was running and still hot from drive and got low 12 volts.

Did some reading and saw someone say sometimes failing alternators will work when cold and then not when hot, so I went in the morning and tested alternator in driveway again. This time I got just under 14.5 volts again, the problem is the engine was reving itself up to maybe 1500-2000 every couple seconds. I say maybe, because the RPM gauge wasn't moving for some reason.

Before this last test the battery had been unplugged, so any codes would of been cleared. After how it ran I tried to pull engine/ecu codes but I couldn't get any, the engine light wouldn't flash it just stayed solid. From what I remember from a few months ago that isn't good sign for the ECU? The engine light is on when key is on, and off when the car starts, as expected, but it doesn't seem to enter diagnostic mode.

Any help would be appreciated.