As the weather has gotten colder (32F +/-2F in the morning), my car is not going into ready mode as consistently as it was in warmer months. I also notice that I have a much better chance of success of going into ready mode if I let the car "pressurize" for about 10 seconds prior to pressing the power button (pressurizing = whatever is going on when you open the driver door and you hear the electric noise of something working (brake pressurization?) in the front of the car that runs for about 10 seconds). In a previous thread, my morning voltage (measured at the battery using a volt meter) was 10.4 volts (roughly 12 - 14 months ago). I've been looking at my voltage in the morning on my scangauge II, and the voltage this morning was 10.0 +/- 0.1 volts. When I hit the power button, the car didn't go to ready, and the voltage dropped to 8.8 to 8.9 volts. I hit the power button again and the car went to ready mode and the voltage was reading 14.6 volts. Driving the car on my commute, it will read 14.5 to 14.6 volts and when I shut the car down at work, the voltage is usually in the mid 12's (maybe low 13) volts. But will likely be in the low 10 volts tonight when I leave. Is it Optima time?