I have a 2004 base C5 w/115,000 miles, only mods are the cold air intake, and cat back exhaust. A little back story of what happened yesterday. Had it out all day with no issues at all. Average outside temp in the afternoon was around 98°. Had the AC blowing nice cold air to keep us at a comfortable 68°. Coolant temps, oil temps, transmission temps, oil pressure all were with in normal all day long. While going over Washington pass, the engine just slowly quit under acceleration. As if someone had pulled the plug. Let off the throttle and it seemed to come back to life. Eased into the gas, and it quit again. If I kept my foot off the gas, engine seemed to idle. But the moment I gave it any throttle at all, it would die. Coasted over to the shoulder, turned the car off, waited about 5 seconds and restarted fine. Put it in gear, and was able to make it up the hill to the rest stop. There was no indication, or warning on the DIC or even a check engine light, nothing. Ran the diagnostics and came up with:
SCM- B2187H
IPC- B0516H
BCM- B2482H/C B0502H/ B0507H
TCS C1287H and C1288 H
Also had B0502H/C B0507H/C

Cleared codes and was able to make it home, roughly 120 mile away with no issues what so ever.
So today I took covers off, and looked all around for loose/frayed/ or even melted wires... none to be found.

She still has the original plugs and wires. Not a daily driver. Any clues or ideas of what to look for would be greatly appreciated before I make an appointment to take her in.

 

Moved to C5 Tech.

 

So it has 16 y/o plugs and wires and prob never had the MAF or TB cleaned. Give the poor thing a tune up with the stuff autozone sells since it prob doesnt matter seeing as it has been 16 years already right?

clean the maf and tb with the cleaner from autozone too.

still running original run flats too?? 🤦🏻‍♂️

 

No it doesn't have the original run flats. Gave those up many many many years ago. But thanks for the witty reply though.

 

Most of the codes are BCM circuit related. I would start with checking all BCM fuses, relays and grounds

 

I've been meaning to clean the ground points. The TCS C1287/C1288 point to the steering position sensor. It's just odd that it was as if someone had pulled the plug, electrical, fuel everything for a couple seconds and the plugged them back in then pulled them back out again. Then it ran fine for the next 100+ miles. It's a head scratcher to say the least.

 

When the steering position sensor goes bad the cars normally start to suddenly break in corners which is pretty scary, but I'v never heard about a power loss due to the bad sensor
Have you got the factory service manual? The problem should be visible in the electrical schematic plans

 

I would disconnect the battery first and do a couple of test drives. If you still get (current) codes you can start from there