HMCGARY

All four codes came up this morning. Battery is less than a year old. Brake light switch was replaced about two years ago when I had problems shifting the gears. really not sure what is going on.

chiph9

Firstly check battery voltage to see if it's charging. It needs to be above 13.8 volts when the engine is running.

Then try disconnecting the negative terminal for about 2 minutes to see if the codes clear. Try and reconnect it with a minimum of sparks. You'll have to reprogram your radio stations, the auto-window down function, the stored seat positions, the stored steering wheel position, and the auto-open sunroof afterwards (see the stickie).

Google searches indicate these aren't really related, and there's a suggestion that there might be wiring damage from rodents. But the brake booster could be affected and this is a safety issue.

HOWEVER - just in case, get a helper to press the brake pedal while the vehicle is running, and you listening to the brake booster pump (you'll have to remove the plastic cover on the driver's side of the engine room). If there's any doubt that the booster is bad - get the vehicle flat-bedded to your mechanic. Without the booster you'll have a very hard time stopping the vehicle.

Chip H.