Your O2 sensors are a separate issue from your radio and bat problem.
Your O2 sensors are controlled by the PCM, which is your power train computer. (Engine/trans) The radio and other electrical accessories are controlled by the BCM, which is your Body Control Module.
You said you replaced the O2 sensors, but are you getting another code? When the engine sets a code for these sensors, it IS NOT saying the sensors are bad. It's only pointing you in the direction of a problem. Such as the wiring/connectors/sensors. And also, your engine could be running a lean/rich condition that is causing the sensors to read something abnormally high/low, which your computer can't compensate for. Sometimes the computer will think there's a problem with the sensor or its circuit.
The proper thing to do when getting these codes is to thoroughly troubleshoot that particular system until the component at fault is found. If a mechanic just goes in to replace parts, you need to find another mechanic, one that knows what he/she is doing.
Your radio sounds as if the power antenna isn't connected properly or has a problem in the wiring. (FM stations need the antenna, AM stations don't) That's why the AM stations are coming in.
Your digital display should fluctuate from anywhere between 13-15 volts (While engine is running). That's normal. But when you engine is off, the bat should read 12.6 (at least)
If you've recently replaced the bat and it's already reading 11 volts, then there's a constant current draw on the bat that isn't shutting off when you turn the car off.
Check to make sure you turn everything off when leaving your vehicle. If the current draw doesn't disappear, then you'll need to have your fuse box probed for the current draw. And if you're unable to locate it this way, have your BCM checked out. These things often go bad and will cause all sorts of electrical gremlins to appear.
Sunday, February 28th, 2010 AT 10:47 PM