sys light on dash
Thread Starter
Intermediate
Joined: Nov 2007
Posts: 42
Likes: 0
From: jacksonville florida
sys light on dash
the "sys" indicator is coming on when my car is cold or for the first few miles until it gets up to normal operating temp. has anyone had this problem or know what it may be
Le Mans Master
Joined: Nov 2006
Posts: 5,032
Likes: 204
From: Greenwood Indiana
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Your battery is about to die. Get it checked quick. The SYS goes away after your alternator charges the system up.
Drifting
Joined: Oct 2001
Posts: 1,648
Likes: 1
From: Denham Springs Louisiana
The "SYS" meassage was appearing on my C4 and it ended up being a loose connection behind the DIC. I found this out by pulling the codes as described here on the forum...it gave me a DIC error code...I took out the DIC and sure enough, the electrical connector was barely hanging on. I reattached it and the "SYS" message disappeared.
Le Mans Master
Joined: Jan 2006
Posts: 5,621
Likes: 206
From: Orlando FL
The "SYS" meassage was appearing on my C4 and it ended up being a loose connection behind the DIC. I found this out by pulling the codes as described here on the forum...it gave me a DIC error code...I took out the DIC and sure enough, the electrical connector was barely hanging on. I reattached it and the "SYS" message disappeared.
I am in a hot climate and it takes its toll on batteries every 2-3 years. For the $50 bucks or so its not worth it to me personally to get stuck either home or away. To me the cost is more than money, I like to be way on the safe side with a battery, not worth the hassle. If I suspect its bad, I’ll change it, but that’s me.
Mike – do a profile so all can see where you are and what you drive. Answers will be better to.
Thread Starter
Intermediate
Joined: Nov 2007
Posts: 42
Likes: 0
From: jacksonville florida
the car is a 94 lt1 i am in florida, the battery is less than a year old but then again the guy that owned it before me put in some stereo system that may not be installed right causing a battery drain. the car is new to me so I am just trying to figure out the bugs
Le Mans Master
Joined: Jan 2006
Posts: 5,621
Likes: 206
From: Orlando FL
The cars system normally use about 0.015 amps- 0.025 amps when all is off and the computer (CCM) is not in the awake state. Anything much more than 30MA is not real normal.
You can always pull the fuse for the radio to see if there is a drain over night. That’s assuming he has not found some other source of power else where. If it is your DD, the alternator will charge it everyday and supply enough current when driving. This will keep it charged assuming the battery is good.
If I go on vacation and the car sits for 2 weeks, I have no problem and no SYS light, this is normal. If you can’t walk away from it for a day or two then there is a problem.
Granted a new battery should be good but that’s not guarantee. And that’s if the battery has been maintained properly and not been drained repeated times.
You might want to measure the battery voltage in the morning before starting the car just to get a base line as what might be happening. Sometimes all the testing will not provide a solid answer and you just have to try a replacement part, a battery in your case to really find out.
You can always pull the fuse for the radio to see if there is a drain over night. That’s assuming he has not found some other source of power else where. If it is your DD, the alternator will charge it everyday and supply enough current when driving. This will keep it charged assuming the battery is good.
If I go on vacation and the car sits for 2 weeks, I have no problem and no SYS light, this is normal. If you can’t walk away from it for a day or two then there is a problem.
Granted a new battery should be good but that’s not guarantee. And that’s if the battery has been maintained properly and not been drained repeated times.
You might want to measure the battery voltage in the morning before starting the car just to get a base line as what might be happening. Sometimes all the testing will not provide a solid answer and you just have to try a replacement part, a battery in your case to really find out.
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Drifting
Joined: Sep 2005
Posts: 1,867
Likes: 3
From: Pasadena Maryland
The car has several computers, ECM, CCM, ABS, and i think there is 1 more? They all communicate over the SERIAL LINK. (Just like a computer has a serial port (OLD MOUSE). Serial ports are slow, 1 way at a time.
Le Mans Master
Joined: Jan 2006
Posts: 5,621
Likes: 206
From: Orlando FL
Basically correct. The serial link is the “communication bus” and is a wire that the PCM, CCM, Brake computer and climate (C68) control unit communicate on. Signals are constantly passed between all the computers for car operation.
If you had a true serial link error it would throw a code. The speedometer is the 'window to the world' to indicate a CCM, module 1 error. The on board diagnostics for the 94 are real good. By connecting pins 4 and 12 on the ALDL diagnostic link will show the codes. But before you get to anxious, you need to learn some basic information on how to do this and not damage anything.
I think of the vette as a rolling computer system with transportation as a bi-product.
If you had a true serial link error it would throw a code. The speedometer is the 'window to the world' to indicate a CCM, module 1 error. The on board diagnostics for the 94 are real good. By connecting pins 4 and 12 on the ALDL diagnostic link will show the codes. But before you get to anxious, you need to learn some basic information on how to do this and not damage anything.
I think of the vette as a rolling computer system with transportation as a bi-product.
Le Mans Master
Joined: Sep 2003
Posts: 5,874
Likes: 0
From: Littleton CO
Look here: http://www.corvettebuyers.com/c4vettes/codes.htmThe info for my '96 isn't very good (and I recently found out that there are more errors than I noticed before), but for your '94 it should at least get you started in the absence of a service manual.
Aftermarket stereos are just as notorious as bad batteries. Yours isn't necessarily draining the battery. The OEM stereo has a dimming circuit which the CCM expects to see. Many, if not most or all, aftermarket stereos don't respond correctly to the CCM command and a code is set. This is the issue with my own car - there is a solution for it that I have yet to do.
Instructor
Joined: Jun 2006
Posts: 143
Likes: 0
From: Plano Texas
To be a little more clear, "SYS" indicates that a code has been set by one of the computer modules. Battery replacment seems to be a common end fix.
Look here: http://www.corvettebuyers.com/c4vettes/codes.htm
The info for my '96 isn't very good (and I recently found out that there are more errors than I noticed before), but for your '94 it should at least get you started in the absence of a service manual.
Aftermarket stereos are just as notorious as bad batteries. Yours isn't necessarily draining the battery. The OEM stereo has a dimming circuit which the CCM expects to see. Many, if not most or all, aftermarket stereos don't respond correctly to the CCM command and a code is set. This is the issue with my own car - there is a solution for it that I have yet to do.
Look here: http://www.corvettebuyers.com/c4vettes/codes.htmThe info for my '96 isn't very good (and I recently found out that there are more errors than I noticed before), but for your '94 it should at least get you started in the absence of a service manual.
Aftermarket stereos are just as notorious as bad batteries. Yours isn't necessarily draining the battery. The OEM stereo has a dimming circuit which the CCM expects to see. Many, if not most or all, aftermarket stereos don't respond correctly to the CCM command and a code is set. This is the issue with my own car - there is a solution for it that I have yet to do.
Racer
Joined: Oct 2005
Posts: 271
Likes: 0
From: Suisun City CA 1992 Coupe LT1 A4
Racer
Joined: Oct 2005
Posts: 271
Likes: 0
From: Suisun City CA 1992 Coupe LT1 A4
Not entirely sure. Changed to an aftermarket stereo last summer. I still haven't done this mod yet for my 92 either. Maybe some other guys may chime in. You will have to do some more research but it seems to be the same problem. This service bulletin is in the C4 audio FAQ.
Last edited by wrw7255; Feb 3, 2008 at 01:28 PM.
Instructor
Joined: Jun 2006
Posts: 143
Likes: 0
From: Plano Texas
Not entirely sure. Changed to an aftermarket stereo last summer. I still haven't done this mod yet for my 92 either. Maybe some other guys may chime in. You will have to do some more research but it seems to be the same problem. This service bulletin is in the C4 audio FAQ.
Racer
Joined: Oct 2005
Posts: 271
Likes: 0
From: Suisun City CA 1992 Coupe LT1 A4
There is probably a reference in your FSM to this service bulletin. I noticed mine flashing after I put in a Sony also but I think it applies to most aftermarket stereos.
