Alternator output is considered within norms when it's between 12.8 and 14.6, give or take half a volt. Battery voltage is usually considered within norms between 11.8 and 13.2, so your reading of 13.4 is actually a little higher than normal. However, under a load test, battery voltage shouldn't drop below 10.5 volts. It doesn't sound like there's a problem with your charging system. The ECM wants voltages between the norms. Have the battery load tested. It's ability to supply the required amount of current within acceptable voltage ranges is more important than the surface charge.
What sort of accessories are installed? Stereo? GPS? Other toys? Make sure they're all fully powering down when you shut the car off for awhile. Pull the negative cable and look for a spark. It should be very tiny, almost unnoticeable. If it's quite noticeable, find what's causing the drain. Such as a short somewhere or an electronic component not being turned off properly. We had one issue recently where it turned out there was an aftermarket stereo and it had a fan attached to the back that ran constantly.
Monday, June 27th, 2011 AT 3:43 PM