Is it possible for a weak battery to cause PCM Problems? I keep getting intermittent OBD readings of 1635 on my Buick Park Avenue. The car will run great for a week and then throw the code and stall out. All tests show everything related, PCM & MAP sensors, are OK. Even replaced the sensors. Took it into the shop and they couldn't find anything. the 72 month Battery is in it'* 68th month and a check on it showed 9.5 volts. Here in Hawaii there isn't the extreme cold problems that can kill a battery but it is weak.

9.5 volts with the engine off indicates your battery is not holding a charge, which can have an effect on the PCM. The PCM takes the 12 volts and converts it to 5 volts for those sensors. Measure the battery voltage when the car is running.

Also, check your battery cables. They might be corroded to the point of lowering system voltage.

cold effects battery capacity not life heat actually wears out batteries faster.

I am surprised that your car will start with a battery at 9.5 volts. The battery has a dead cell and should be replaced now. It could mess up many things in your cars electronics.