ronwc

I just got a 97 coupe about a week ago, this is my third C5 and I usually do all my own work although my patience isn't as long as it used to be. The only problem I had when picked up was the AC control would turn on and off randomly. I think I figured out that was an ignition switch problem and was going to order a new one.

Been driving great, everything working till last night. Got in to go out and battery was about dead, it is a 2 year old red top. I did notice that the AC lights and shifter lights were on which I guess is what ran down the battery. since lights were on, I disconnected the battery to let it charge most of the night.

When I get in now to start it, it will crank and run for about 5 seconds, so I guess it is some kind of security problem. the codes I got today are P1571 HC, P1626HC, U1255H, U1160HC, U1176HC, U1016H, U1064H and U1255H. I tried to clear and crank but same 5 second run.

Most of the other items came up as no communication. I did notice some things in the car works and some didn't, AC seem to come on, radio blank, door locks work but no windows or inside lighting. Also when hooking battery back up the AC and shifter lights seem to be off. When turning on the dash and headlights, they work fine, but now radio, AC and shifter don't light up.

Help me get this thing going again.

Bill Curlee

To the LEFT of the BCM are two thin connectors/ Find the one with FOUR wires and pop the top off of it. See if that resolves your no start issue.

Report the results.

Bill

ronwc

Bill, Just went out and look and I don't see a thin 4 pin plug left of the BCM. The BCM has three larger plugs to it. And above a three pin plug. When I unplugged it I noticed two of the wires on one side are not connected to anything, looked corroded off, tried to add pic but not uploading correctly. Disconnected it and tried to start but battery weak again, lights back on AC and shifter light (were maybe never off, can't see well in daylight). Thanks for your help, I appreciate it.

Bill Curlee

ronwc

OK, Found the plug you were talking about, they were tucked behind in the “pocket”. I took out fuse to turn the AC lights off but shifter light is still on and battery somewhat drained so can’t start. I guess I could jump it off my explorer. Anyway have the 4 wire plug disconnected and will try again to start.

ronwc

Will try to start in the morning, if not enough battery will jump off the explorer. It was starting ok this morning but would shut off fairly quickly after about 5 seconds.

BigGun

Take the battery to an auto parts store and have it load tested. You can't do anything meaningful until you are sure about the battery. A C5 will not run properly with a weak or dying battery.

ronwc

Well, good news is the battery fully charged last night so going to try to start with the one connector unplugged as Bill suggested. If that doesn't work, going to take console out and check for any pinched wires. I recently had it out to fix the AC control. I may disconnect AC unit and or radio to try that. It seems that the radio has no lights or anything showing at all, so could be that. Going out to work on it now, will try report back in an hour or so.

ronwc

I got battery charged, hook it back up and tried starting with the 4 pin bus disconnected as Bill suggested. Same thing, started for a few seconds and cut off. Then I took out AC unit and radio, but same thing. Then pulled codes, cleared and tried but same thing, a few second run. Here are the codes that keep coming up – P1571HC, P1626HC, U1160HC, U1176HC, U1064H, U1255H, B2282H, B2284H, B2283H.

I also tried disconnecting battery after all done, and reconnecting but still the same. Battery is fully charged. The light is staying on the shifter. Some of the functions are working in the car, such as dash lights, headlights, doorlocks, gas release and AC. Some functions not working at all such as radio, power windows and trunk release.

I was going to change out the ignition switch anyway because AC was intermittent, and now I wondering is my key is not making good contact to turn off the security system. I cleaned it, but the resistor on the key is fairly wore down. Maybe get a new key made first.

I have owned many C4 and C5 vettes, and usually do all my own work, but this one is starting to get to me. I’ve only had the car about a week and it has always run strong and every worked fine except AC would go on and off. Right now have stiff have AC and radio out. Will probably go ahead and disconnect battery since shifter light is staying on.

Any help or ideas would be greatly appreciated. I think the whole thing boils down to getting the security to turn off, not sure why it cam on anyway unless bad key or ignition module.

Bill Curlee

DTC P1571 Traction Control Torque Request Circuit
P1626 Theft Deterrent System Fuel Enable Circuit

P1626 is your MAJOR no run/start issue.. Get a spare key or a new key with the correct resistiance chip and see if that clears the issue. Also could be a bad sensor on the front of the ignition switch that isnt reading the chip on the key

Bill

ronwc

Thanks for the advice, I think that’s exactly what I have it narrowed down to, the key and or ignition switch, going to replace both tomorrow, will let you know what happens.

ronwc

Ok, guys, I went out and bought a new ignition switch, which I needed anyway for the AC being intermittent, and a new key today. I was sure this was going to fix all my problems. Put all in and still the same old problems, starts for about three seconds. Some stuff works, some doesn't. The new switch does appear to have fixed the AC control.

About the only thing left I can think of is the reader on the cylinder. If I buy a new cylinder, does it come with a new key or can I use my old ones. And do I have to do some type of programming to get it to match my car.

This is really starting to get to me. I don't mind working on it some, but would like to see some progress.

Bill Curlee

When you purchase a new key cylinder,, it comes with a new chip sensor. Take the new cylinder & your OEM Keys to a local lock smith. I recommend that you purchase a new key blank with the correct resistance chip and have the lock smith cut you a new key.

The lock smith can rekey your new cylinder/sensor to your OEM Key.

BC

ronwc

Ok, Here is where I am at today. I am trying to approach this problem logically, but it is getting difficult. I really thought changing out the key switch would solve the problem, also got another key made thinking that might help with any connection problem, and I wanted a spare anyway. I don’t think this was money wasted because it did seem to fix my AC intermittent issue. I was going to change out the cylinder next, thinking it may be bad connection with key and sensor, but I really don’t think that’s the problem, especially after buying a new key.

However, bottom line is car has some strange symptoms and will not run longer than about 3 seconds. As mentioned before, I have only owned this car for about a week, and it ran great for the first 5 days (no problems or unusual codes) and has been down 3. I have owned 2 other C5’s, and know a little about them, but this problem has me stumped.

The main (strange) symptoms are AC and shifter illumination lights stay on when battery is connected. And some things work normally (door locks, headlights, AC) and some things don’t work at all (trunk release, windows, radio) which indicates to me a possible BCM problem. I am going to unplug and check BCM connections today. I have already checked and see no indication of any corrosion or water damage. Also check buss strips closer.

When I try to pull up codes now I mainly get a lot of no comm (I will check them again today). After I check the connectors on the BCM, I will check some of the grounds. With the 1626 code, it’s not going to run. So I guess it could also be a PCM problem.

c5chines

Possibly low oil pressure fuel cut off?

Bill Curlee

The C5 DOES NOT,,, have a low oil pressure cut off.

BC

Bill Curlee

What DTCs do you still have?? Clear ALL the DTCs. Crank and start the engine and if,,, it shuts down,,,,,, WITHOUT changing the position of the ignition switch, read and post your DTCs.

Do you still see: P1626 Theft Deterrent System Fuel Enable Circuit ??

Another thing to verify. The connector for the Ignition Switch can have damaged female pins in the harness connector. Here is what a damaged female pin looks like. Check yours and see if you have the same conditions:

The black connector has damaged larger pins. They ware compressed and make poor connection with the male pin in the switch.



Bill

ronwc

Here's the latest. I worked and tried everything I could for three days off and on. Found a local corvette expert mechanic and had it towed there. He checked out and tested things for a day or two and finally determined that the BCM was not communicating right. I ordered a used one on ebay for $229, should be in by Monday, hopfully we can get things back on track and running again.

ronwc

Got some good news from the repair guy, new (used BCM) part came in today, he put it on, did a little programming and it is ready to pick up in the morning.

Can't wait to get in and go, haven't driven it in about a week. The BCM cost me $229 and he only charged me $250, could have been much worse.