One more thing ... it seems there always is

The smart chargers often have a time limiter so that if it does not reach the
target, it turns off anyways. Overnight it would be fine, but you are trying for
48+ hours.

To outsmart it, once a day, unplug it, disconnect it and start all over again as normal.

 

Since Thursday last week I have been charging the the new battery and I haven't had a failure since. Although the weather has been much warmer never less than -20C. It is concerning that the battery seems to discharge with normal use.
So all weekend the battery was on the smart charger. I didn't drive the car. Monday morning I unplugged the charger and took off to work. 44 km one way in the dark. I drove it at lunch for about 6 km. I then drove home another 44 km again in the dark.
I hooked up my charger and the display shows LO and in about 5 minutes it showed 60%. It appears the battery is not charging via the alternator. I imagine if I run the car for a few days and the battery keeps getting discharged I would eventually get the P0116 code again.
I will have to do some testing this weekend and find out what the output voltage of the alternator or should I say generator per the shop manual is.

 

Since leaving the battery tender on in the evenings there has been no further recurrence of the problem. As of last night I will not plug the battery charger in and see how long it takes to get the P0116.

 

Since Tuesday Jan 27 I stopped plugging the battery tender in. I measured the battery voltage every morning and connected my ODB2 reader.
On Tuesday Jan 27th it measured 12.53 at the battery and dropped day by day 12.45(Wed), 12.33(Thurs), 12.23(Fri) and finally Sunday it had dropped to 12.01v and the P0116 reappeared. The code appeared as I have seen before, just turning the ignition switch to on, not starting. I reset the code and started and everything was normal.
So it appears the battery is discharging over a number of days. On my car the low voltage seems to kick out the P0116 which I will call a red herring despite changing the ETC sensor.
When I checked the voltage with the car running I get 14.55V which should be enough to charge the battery.
The battery is new, could it be faulty?
Unless the car while running is consuming all Amps put out by the alternator the battery should be charging.
When the battery does discharge down to the fault voltage level, it does take my smart charger almost 24 hours to get it back to 100%.
I cleaned the grounds at the battery and will do a measurement for leakage current to see if something is draining the battery overnight.

 

Rick,
I think you are looking at a voltage problem and even though the battery is new I think it may be bad. A new battery being bad happens far more times then it should.


When I bought my jag the dealer told me to lock it all the time even if it is parked in a locked garage. Like most cars today they are very power hungry and even when you turn the car off some systems are still running. The dealer said by locking the car it puts it to sleep limiting its power draw.


IT takes the car's alternator a long time to charge a low battery. I got the same code and symptoms as you. I had left the head lamps on for hours with the car turned off before turning them off. Two days later in the morning the car turned over slower then usual but did start. The following morning I got the code and no temp gauge. Cleared the code and as you know everything comes right back to normal. That night I trickle charged the battery over night and have not had the problem again in over two months, (knock on wood)


A voltage problem, either battery, bad grounds or a bad alternator. In my case it was a low battery. I suspect in your case a bad battery,