[N_Jay]

After a few weeks out of town, my battery was 100% flat. Not a click, not a glow of a light and needed to use the fuse box terminal to pop thr hood.

I have it on a good charger, and will replace it if it does not come up to full voltage and crank well.

So, what am I in for in terms of programming and software issues?

[XR4Tim]

Likely just a bunch of low voltage faults stored and a steering angle sensor calibration fault that will clear once you drive the car in a straight line for a few feet.

[N_Jay]

Likely just a bunch of low voltage faults stored and a steering angle sensor calibration fault that will clear once you drive the car in a straight line for a few feet.

Thanks.
I usually try to keep a battery on cars with ECUs.
This was so dead my charger would not even start.
I had to parallel a jump box for a few min.

I give it 50/50 that it comes up low standing voltage.

[fpena944]

Likely just a bunch of low voltage faults stored and a steering angle sensor calibration fault that will clear once you drive the car in a straight line for a few feet.

Thanks.
I usually try to keep a battery on cars with ECUs.
This was so dead my charger would not even start.
I had to parallel a jump box for a few min.

I give it 50/50 that it comes up low standing voltage.

Any idea how old that battery is?

It's surprising how quickly P-cars drain batteries when not in use.

[N_Jay]

It is dated 12/20.

Storage and lack of use is hard on a battery.
All new cars drain batteries. Too many computers and to hard to code realy good sleep routines.

Think about that dripping faucet adding uo to hundreds of gallons in a few weeks.

The battery is at 12.6 after coming off the charger, which is a little low.
I like to see 12.7 on an older battery.
But I usually don't start seeing issues till resting voltage gets down to abot 12.4

[worf]

So, what am I in for in terms of programming and software issues?

What year and model car?

All new cars drain batteries. Too many computers and to hard to code realy good sleep routines.

Depends.

[N_Jay]

So, what am I in for in terms of programming and software issues?

What year and model car?

All new cars drain batteries. Too many computers and to hard to code realy good sleep routines.

Depends.

2012 987.2 Cayman Base

Yes, they all drain at different rates, but they all drain a hell of a lot more then pre-computer car.

[worf]

2012 987.2 Cayman Base

Yes, they all drain at different rates, but they all drain a hell of a lot more then pre-computer car.

Does the 987 still have the ‘traditional’ fuse/relay panel(s)?

The 9[98][12] did away with most of the relays and added a software-controlled ‘distribution’ box. When those “go to sleep” they really Go To Sleep. As in: single-digit mAh sleep.

In “classic” cars, drain of more than 20-30 mAh is usually a sign of a stuck-on relay, failure of a ‘black-ish’ box connected to the 30 Bus directly, or a wiring problem. The latter usually (IMO) due to thoughtlessly installed aftermarket ‘lectric stuff and/or bad service performance.

The 87+ 928 has 5 to 9 ECUs and one or more ‘black-ish’ boxes (depends upon definition of ECU.) Battery drain is often, wrongly, considered a “design defect” when in reality the drain is something to be fixed.