80K maintenance problems

As I was finishing the transmission oil filter change 0n my 2013 TDI SE my dash lit up when I started the vehicle to bring it up to temperature. After finishing the transmission, I shut the vehicle down and read the codes that were responsible for the lights. First one that caught my eye was a bad O2 sensor, these had just been checked and replace with the diesel recall a couple of weeks prior. A clearing of these code bought me new ones when I started, ran in place and rechecked. A 4629-ECM Power Relay load Circuit, and 17262 Terminal 30. Checked each of the relays as suggested in another thread, all were good. Only affect electrical component during this maintenance was the removal and replacement of the battery to gain access to the transmission filter. After starting it several times in a row, it failed to start on the fourth try-power flashed on and off at that point. Had no other sign of any problem up until this time. A quick battery check showed that it had gone bad, the movement of taking it out and put back in had been enough to disturb the internals. Replaced battery cleared codes and started and drove, by the time I went 100 foot the rest of the codes for the ABS, steering, and tires pressure cleared. Doing maintenance is not a good time for something like this to happen!

better now in your driveway than later in the snow out in a parking lot. If it was that close to failure it would have been soon. I think you got lucky.

My battery decided to give out several years ago 10 pm, leaving on a long trip next morning early. But I felt lucky also. could have lasted 12 more hours, until at a rest stop middle of nowhere. It gave out at the fuel station across street from Walmart. I usually avoid that place, but they were open and there.

So what happened? I didn't see anything out of the ordinary.

What was the "quick check" you did? Doing any kind of check on a dead battery usually gives you erroneous results.

What I do is put it on a charger overnight the day before it goes back in the car and if the charging amps gets down to two and the battery voltage is correct, the battery is good. The charging amps on a bad battery will stay at 4 to 6 amps and if there are shorted cell(s) the battery voltage will be low.

Of course a 5+ year old battery owes you nothing.............