HIS S-197

This morning driving into work I notice a "Low Battery" Warning in the OBC, the LCD of the radio, AND the battery gauge turned red ON the L.
The warnings flashes as I am pulling onto base, so I park it and figure I'll take care of it at lunch.
There is no yellow battery light, so I absolve the charging system/alternator and figure it's about that time for a new battery.

::3 HOURS LATER::

I walk out to my car with a coworker at lunch to pull the battery and head to the nearest AutoZone.
There wasn't enough juice to roll up my windows in the morning but I decide to try to crank it just for fun and...
IT MAGICALLY STARTS RIGHT UP (with the battery gauge charged slightly below the middle)

We pull the battery anyway and take it to AutoZone to have it checked.
They say the battery is bad, so I buy a Duralast Gold replacement.
I install the new battery, and I notice the crank takes a little longer than usual.
I also notice the OBC now displays "Tire Pressure Sensor Fault" with the yellow TPMS warning light illuminated in the dash.



Does anyone have any clue...

A: Why a new battery would cause a TPMS fault?
B: Why a new battery would cause a longer crank? (I could just be imagining things)
C: How the battery magically recharged itself without the car running?

duckbubbles

Have you driven the car since? Sometimes it takes a little while to clear the fault.

I recently replaced my battery and had no problems.

Frank

07BLACKGT

****ing s197s.

I have no idea.

danzcool

When you disconnect the battery the TPMS will sometimes trip until you drive for a bit. The new battery may have been sitting on the shelf for awhile and may not have had a full charge.

Goldenpony

One thing not many people know is that when you buy a new battery, it should always be brought to full charge with a battery charger before installing. Experts say this will greatly extend the life of any new battery. Just sayin'...

alkemist

+1

Need to drive for some miles and the code should clear itself. If not, then you will have to look into it further. It's common for TPMS symbol to light up after your battery has died, jumped or new battery.

JayyVee

I had not heard this before - thank you, if this is the case this is great advice, I will give this a run next year when it's battery time!

07BLACKGT

^Yeah, but be careful if you get a gel type battery (optima). Typical battery chargers will fry them. They will need to be charged with a trickle charger.

HIS S-197

UPDATE:

The code cleared itself after the 30 minute commute yesterday. HUZZAH!


I had never even considered this but it is valid advice. I don't know if my daily commute is long enough for the alternator to entirely charge the battery, so I'll swing by AutoZone and have them fully charge it for me.

I'm still curious as to how exactly the bad battery charged itself without the car running, but at this point I'm just going to let it ride.

Thank you to everyone for the replies. I appreciate all the help.

Art161

It's one of those mysteries with no definite answer. One possibility is that since the battery was bad, there could have been an intermittent internal short. Or the battery could have been sulfated and some of the chemicals moved around a bit with the car sitting, due to temperature change under the hood or some other reason. Or it could be magic.