I've been doing a bunch of searches on here since my 2000 6speed coupe went haywire yesterday upon starting and haven't found an exact repeat of what's been happening with my car.

Everything has been running fine until I get in my car yesterday to run and get a quick hair cut, turn the key and all the electrical goes crazy, there's a clicking sound coming from what I assume to be the BCM, and the engine isn't even close to wanting to turn over. After trying to start it several more times, and even trying to jump it with my girlfriend's car thinking it's the battery, it has the feel of an extreme short. The lights are very dim, the guages are bouncing around, the dash lights coming on and off, etc when trying to start the car only. Everything remains dim for probably 10 seconds after a start attempt, and then the lights slowly come on one by one, and if the radio was on during the start attempt, it continues playing with just treble, and then the bass slowly comes back. I also noticed as i apply pressure to the breaks, the lights dim while trying to start the car. At first it wouldn't even come on enough for me to pull any codes, and finally after a few tries, I could at least pull a few codes. The first round of codes were:

BCM B0503 H
BCM B0507 H
BCM B0508 H
BCM B2587 H
BCM B2592 H
LDCM B2282 H
LDCM B2284 H
RDCM B2283 H
RDCM B2285 H
SCM B0851 H

After disconnecting the battery and removing the BCM to do a quick inspection, checking the connections in the doors and shaking them, and hooking everthing back up and trying to restart, same thing happened but this time the only codes that popped up were:

PCM P1516 H C
PCM P1517 H C
PCM P1518 H C

It also went into "Low Voltage" and "Reduced Power Mode" in between the first and second round of jacking with the car, but as of this morning when I tried to start it again, the reduced power and low voltage stuff had gone away.

My main complication is that this is my daily driver, and i'm headed out of town wednesday through the weekend, so have limited time with the car to poke around. I was planning on having it towed to Corvettes of Houston here in town and having them look into it, but didn't know if there was something easy that i may have overlooked in my limited time messing with the control modules.

Nothing is wet in the car, the ac isn't leaking, and i haven't just done a car wash or anything that would introduce water into any modules recently. It's 95 degrees and sunny here in houston, so that should keep moisture down if there was any in there. There hasn't been any odd electrical issues before, this just popped up out of nowhere. The car has run like a champ the last 9 years i've had it.

Any ideas or help would be appreciated.

 

Try turning your headlights on before starting it to see if they are dim as well. If they are you probably a bad battery connection at the battery or ground or the underhood eletrical center.

 

Just some help with the codes:

P1516 Throttle Actuator Control (TAC) Module Throttle Actuator Position Performance
P1517 Throttle Actuator Control (TAC) Module Performance
P1518 Throttle Actuator Control (TAC) Module Serial Data Circuit

Sounds like you may have a shorted wire at the throttle body. Possibly try disconnecting throttlebody harness and check for loose or bad wire? I''m no expert by any means but might help a little. Maybe the TAC module is shorted internally.

 

I appreciate the replies. I'll try to test the battery tonight to rule that out.

 

Thanks again for all the help, turns out my no load charge was 12.0. Took a cab to the auto parts store and picked up a new battery, still under warranty. Installed it and she fired right up. I cleared all the codes and everything stayed gone after another restart except:

RFA U1096H
RFA U1064H
RFA U1016H

Ive had dead batteries over the years and none acted close to this, it was wacky.

Thanks again, now I can just look like an idiot on here instead of at Corvettes of Houston after a tow. This forum and its helpful members are a great resource, and I really appreciate the help.

 

Good call on the battery. Always the first place to start with any electrical gremlins in the C5's. These cars really do require a battery in good health. Glad you got it worked out.