So this weekend, i was driving my '99 up north in michigan and the security light comes on...then the DIC reads "service vehicle soon" and then a few miles later both of these disappear. After parking the car for two days, i went to start it and it will only run for about 1 sec. then the low fuel, low voltage, service tire pressure monitoring system, and service active handling lights came on, the windows would not roll down, no power to the stereo, and no power to the HVAC. then maybee two minutes later everything was back to normal. the next day at the ice cream shop, this whole process repeated. dealership couldnt find anything wrong with it and just cleared a security code. you guys have any thoughts?

 

Battery dying???

 

Anytime the words "weird" and "electrical" are used in the same sentence, it usually means "bad grounds".

 

There are many possibilities, but if it were my car, I'd start with checking the battery connections (on both ends of the cables) for corrosion or loose connection. Check the ends where they crimp to the cable, too. Then I'd check the starter connector that goes to the battery. The post should be firm. Many posts recently have found that the bakelite connector at the starter has burned or corroded. If all that looked good, have the battery load tested. Watch the voltage display on the DIC while running to see if the voltage varies greatly from the alternator. If the regulator in the alternator goes bad, you can get many, many warnings like you describe. Then go to the grounds and clean them. That's the pattern I'd try.

 

If the battery and it's connections are good then the second thing I would look at is the BCM. Is the passenger side floor damp or wet around the BCM? if not then it may be about to die.

Next time you get the "service vehicle soon" follow this link to see what codes you have and post them here, you don't need the dealer to look at or erase any codes you can do it yourself.

https://www.corvetteforum.com/techti...D=26&TopicID=1

 

well its not the battery and connectors, i just installed a new one not too long ago. The weird thing with all those idicator lights was that the low fuel light was on, yet the fuel gauge read 3/4 of a tank (true reading), the low voltage ligh was on, yet the gauge and digital display read 13.2 volts...the car just did the service vehicle soon light again this morning, so ill go pull the code on it soon. As for the starter and such, the car would turn over just fine...it just wouldnt stay running. there was power to the lights and engine, and yet no power was being sent to the stereo/HVAC/or power windows and locks until the key was in the "start" position...

 

So here is what the DIC had to say for codes:

PCM--No codes

BCM-U1255H, U1016H, U1096H

SDM-U1000H, U1016H, U1040H, U1096H, U1064H

IPC-U1064H, U1040H, U1176H, U1088H, U1160H

Radio-U1096H, U1064H

HVAC-U1064H

A0-LDCM- B2282H, B2284H, U1255H, U1064H, U1016H, U1096H

A1-RDCM- B2283H, B2285H, U1255H, U1064H, U1016H, U1096H

A6-SCM-U1255H, U1016H, U1064H

B0-RFA-No codes

There was no active 'service vehicle soon' warning, but it did throw the warning this morning.

 

Just because you have a new battery doesn't mean it's good. In fact, it may be an indication that changing the battery created the problem, either with loose connections, corroded connections or even a bad new battery. The starter connection I described doesn't show up as a starting problem, but as a voltage problem causing all sorts of electrical issues. I didn't make it up, do a search and you'll find two recent posts with errors like you're getting where the end resolution was the connector on the starter being loose or corroded. One has pictures of the charred bakelite on the starter stud. If you don't check it, you can always pay the dealer to do it. Your choice.

 

Your car has a similar problem that my 2003 stock C5 had. While driving cross country in an ice storm I was stopped on a highway waiting for an accident to be cleared when I got out to stretch my legs while the car was running when I got back in I shut the door and all the HVAC controls went out, the radio went out, the lights went out, "engine at reduced power", and all the drivers side door control panel buttons would not work. Thus my window would not go up, door locks would not work, seat memory would not work etc... The accident clears and I start driving down the highway and I try opening and closing the drivers side door, all of a sudden everything works again??? Weeks later when back home I read a post by Bill Curlee regarding the wires that are inside the black rubber accordion that connects the drivers door with the body of the car. Sometimes there are some defective wire connectors showing bare wires that may short after opening or closing the door. Sometimes it works and when you open or close the door the wires shift and suddenly nothing works. The quick fix is to simply grab the black accordion and twist it around a bit then check if the window works. Its easiest to do it at nite because you'll notice that the drivers side door control panel will not even illuminate when shorted. Thus you can turn the lights on and twist the accordion and quickly notice when the control panel lights up and you'll know if that's your problem. The permanent fix is to find the short and repair it but in my case I twisted the accordion and corrected the problem. The wires didn't short out for a month. But the problem did happen again and I did the twist again and the problem has not reoccured.

I can't afford/trust the dealership way of diagnosing and solving problems. This forum has been absolutely great with helping each other solve their problems for the least amount of money. I don't know how different your 99 is from my 2003 but since we have similar symptoms I feel its worth the shot to atleast eliminate this possible cause. My problem was easy, simple and cheap to diagnose and worth a try in my opinion.

Goodluck

Update
Two years later the problem happened again so I pulled the rubber accordion boot off and pulled out the connectors. I pulled the connectors apart to find a little green corrosion and then did the pull test on each wire to see if any were loose. No wires were loose so I cleaned the corrosion with some electrical contact cleaner in a spray can. I also read this post... http://forums.corvetteforum.com/c5-t...cs-inside.html
which showed that some of the connectors may need to be tightened up because you may see a larger gap on the female connector. Finally I wrapped the connectors up with electrical tape to try to prevent further corrosion. So far this fix is working for me.

I see below N Bawls has a good post and fix for this topic too...
http://forums.corvetteforum.com/c5-t...k-careful.html

Good Luck to all and thanks for your contributions!

 

Thanks for the replies guys. Jersey, that sounds exactly like my problem! I forgot about the 'reduced engine power' display...ill play around with that tomorrow evening. Ill go for a crawl and check the starter connections as well...hopefully one of these two is the culprit, because im not sure to make of those codes indicating loss of communication between various electronic control modules. I tested the batt earlier this evening, wire brushed and then reattached the connections, and everything checked out fine.

 

There are two ground connections I want you to check, I had some similar issues and these were found to be loose (finger tight). The first is just below the battery and is the ground for the battery. It is on the frame rail itself and obscured by the plastic heat shield that surrounds the battery. The second is the one on the engine block above the starter but below the exhaust manifold between #6 and #8 cylinder. Pull the plug wire off to get at it better. One of them might be loose now and the looser it gets the wierder things become. Good luck.

 

Alrighty, Ill give the grounding points a look while im poking around with the starter wires...gotta love the gremlins in the electrical system ...Thanks for all your input everyone

 

I'm very interested to know what you find, My 03 z just started doing that this morning. All I have done to it, is replace the battery 3 days ago.

 

Similar issue as Jersey. Here is the post with my diagnosis and repair.

http://forums.corvetteforum.com/show....php?t=1602677