"sys" Flashing On The Cluster???
03-15-2008, 11:17 PM
#1
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"sys" Flashing On The Cluster???
What does it mean when "sys" flashes sometimes in the center of the cluster. Is the ecu detecting something? I usually drive with the temp gauge and sometimes it gets replaced with "sys" flashing. It doesn't happen all the time. It seems like it happens more at night. Can't figure it out. Nothing seems to be wrong with the car.
Any help?
Any help?
03-16-2008, 10:54 AM
#3
Elite Torch Red Member
9 times out of 10 it is a weak battery.
03-16-2008, 12:21 PM
#5
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The sys indicator is an electrical problem indicator that usually comes on with a weak battery, and electrical problem in the dash (rare), or an aftermarket radio change (because the new radio doesn't have the proper resistance value).
03-20-2008, 06:14 PM
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This doesn't do you much good without the illustration, but at least you will know what you're looking for.
This was a TSB issued for this problem:
Radio - Aftermarket Unit May Set DTC`S 72 and 74
Number: 93-68-9A
Section: 9A
Date: DEC. 1992
Corporate Bulletin No.: 238311
ASE No.: A6
Subject:
AFTERMARKET RADIO MAY SET DTC'S 72 AND 74 IN CCM
Model and Year:
1990-93 CORVETTE
APPLICATION:
1990-93 Y-car
CONDITION:
On the 1990-93 Y-car, Diagnostic Trouble Codes (DTC's) 72 and 74 may be set in CCM if an aftermarket radio is installed. "SYS" will be displayed in the LCD section of the cluster, and the DTC's will be displayed when the diagnostic mode is entered.
CAUSE:
With an aftermarket radio installed, DTC's 72 and 74 are likely to be set because the LCD and LED dimming lines to the radio have gone to an open circuit, because these inputs do not exist in an aftermarket radio.
CORRECTION:
1. Disconnect negative battery cable.
2. Remove the radio control head, following the directions in the Service Manual, Section 8C. This will allow access to the radio control head wiring.
3. Add 1K ohm, 1/2 watt resistors as shown in the illustration. The resistors are available from a local electronics supply store, such as *Radio Shack. The resistors should be connected to a 12 volt ignition-switched circuit. For 1991 to 1993, there is an auxiliary power pickup in the console. For 1990, ignition circuit number 300 should be used. See Section 8A for wiring details.
4. Reinstall the radio, then reconnect negative battery cable. Clear the CCM DTC's as shown in Section 8D, and verify proper operation.
If further information is needed, contact the Corvette Action Center at 1-800-457-8388. Hours of operation are 6:00 a.m. to 4:30 p.m. Central Time, Monday to Friday.
"We believe this source and their equipment to be reliable. There may be additional manufacturers of such equipment. General Motors does not endorse, indicate any preference for or assume any responsibility for the products or equipment from this firm or for any such items which may be available from other sources."
This was a TSB issued for this problem:
Radio - Aftermarket Unit May Set DTC`S 72 and 74
Number: 93-68-9A
Section: 9A
Date: DEC. 1992
Corporate Bulletin No.: 238311
ASE No.: A6
Subject:
AFTERMARKET RADIO MAY SET DTC'S 72 AND 74 IN CCM
Model and Year:
1990-93 CORVETTE
APPLICATION:
1990-93 Y-car
CONDITION:
On the 1990-93 Y-car, Diagnostic Trouble Codes (DTC's) 72 and 74 may be set in CCM if an aftermarket radio is installed. "SYS" will be displayed in the LCD section of the cluster, and the DTC's will be displayed when the diagnostic mode is entered.
CAUSE:
With an aftermarket radio installed, DTC's 72 and 74 are likely to be set because the LCD and LED dimming lines to the radio have gone to an open circuit, because these inputs do not exist in an aftermarket radio.
CORRECTION:
1. Disconnect negative battery cable.
2. Remove the radio control head, following the directions in the Service Manual, Section 8C. This will allow access to the radio control head wiring.
3. Add 1K ohm, 1/2 watt resistors as shown in the illustration. The resistors are available from a local electronics supply store, such as *Radio Shack. The resistors should be connected to a 12 volt ignition-switched circuit. For 1991 to 1993, there is an auxiliary power pickup in the console. For 1990, ignition circuit number 300 should be used. See Section 8A for wiring details.
4. Reinstall the radio, then reconnect negative battery cable. Clear the CCM DTC's as shown in Section 8D, and verify proper operation.
If further information is needed, contact the Corvette Action Center at 1-800-457-8388. Hours of operation are 6:00 a.m. to 4:30 p.m. Central Time, Monday to Friday.
"We believe this source and their equipment to be reliable. There may be additional manufacturers of such equipment. General Motors does not endorse, indicate any preference for or assume any responsibility for the products or equipment from this firm or for any such items which may be available from other sources."
03-20-2008, 08:41 PM
#7
Burning Brakes
I have the same problem and was going to do the TSB fix, but it might be the battery also, so I was wondering is there a way to read the codes to find out for sure, battery or radio? Is there a way we can get codes off the CCM?
03-20-2008, 08:44 PM
#8
Racer
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this is the problem I was expericencing and once I shut off the car, and restarted it, it went away.
that was when I was starting it about once a week in 5 degree weather.
if I put a battery charger on it and then started it, it never happened.
weak battery syndrome ......
that was when I was starting it about once a week in 5 degree weather.
if I put a battery charger on it and then started it, it never happened.
weak battery syndrome ......
03-20-2008, 10:19 PM
#9
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Checking the codes is simple, on my 91 anyway. I started a thread earlier. Refer to "downloading codes on a 91".
I just did mine. I got a C72, H72, H46, and 1.0. Now all I have to do is decypher them. I know the C72 is because of the aftermarket radio thing, but I don't know what the H72 or H46 are. For the C72, I'll have to put the resistors in per the TSB. But if anyone has other methods, I'm all ears!
I just did mine. I got a C72, H72, H46, and 1.0. Now all I have to do is decypher them. I know the C72 is because of the aftermarket radio thing, but I don't know what the H72 or H46 are. For the C72, I'll have to put the resistors in per the TSB. But if anyone has other methods, I'm all ears!
03-21-2008, 10:07 AM
#10
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This doesn't do you much good without the illustration, but at least you will know what you're looking for.
This was a TSB issued for this problem:
Radio - Aftermarket Unit May Set DTC`S 72 and 74
Number: 93-68-9A
Section: 9A
Date: DEC. 1992
Corporate Bulletin No.: 238311
ASE No.: A6
Subject:
AFTERMARKET RADIO MAY SET DTC'S 72 AND 74 IN CCM
Model and Year:
1990-93 CORVETTE
APPLICATION:
1990-93 Y-car
CONDITION:
On the 1990-93 Y-car, Diagnostic Trouble Codes (DTC's) 72 and 74 may be set in CCM if an aftermarket radio is installed. "SYS" will be displayed in the LCD section of the cluster, and the DTC's will be displayed when the diagnostic mode is entered.
CAUSE:
With an aftermarket radio installed, DTC's 72 and 74 are likely to be set because the LCD and LED dimming lines to the radio have gone to an open circuit, because these inputs do not exist in an aftermarket radio.
CORRECTION:
1. Disconnect negative battery cable.
2. Remove the radio control head, following the directions in the Service Manual, Section 8C. This will allow access to the radio control head wiring.
3. Add 1K ohm, 1/2 watt resistors as shown in the illustration. The resistors are available from a local electronics supply store, such as *Radio Shack. The resistors should be connected to a 12 volt ignition-switched circuit. For 1991 to 1993, there is an auxiliary power pickup in the console. For 1990, ignition circuit number 300 should be used. See Section 8A for wiring details.
4. Reinstall the radio, then reconnect negative battery cable. Clear the CCM DTC's as shown in Section 8D, and verify proper operation.
If further information is needed, contact the Corvette Action Center at 1-800-457-8388. Hours of operation are 6:00 a.m. to 4:30 p.m. Central Time, Monday to Friday.
"We believe this source and their equipment to be reliable. There may be additional manufacturers of such equipment. General Motors does not endorse, indicate any preference for or assume any responsibility for the products or equipment from this firm or for any such items which may be available from other sources."
This was a TSB issued for this problem:
Radio - Aftermarket Unit May Set DTC`S 72 and 74
Number: 93-68-9A
Section: 9A
Date: DEC. 1992
Corporate Bulletin No.: 238311
ASE No.: A6
Subject:
AFTERMARKET RADIO MAY SET DTC'S 72 AND 74 IN CCM
Model and Year:
1990-93 CORVETTE
APPLICATION:
1990-93 Y-car
CONDITION:
On the 1990-93 Y-car, Diagnostic Trouble Codes (DTC's) 72 and 74 may be set in CCM if an aftermarket radio is installed. "SYS" will be displayed in the LCD section of the cluster, and the DTC's will be displayed when the diagnostic mode is entered.
CAUSE:
With an aftermarket radio installed, DTC's 72 and 74 are likely to be set because the LCD and LED dimming lines to the radio have gone to an open circuit, because these inputs do not exist in an aftermarket radio.
CORRECTION:
1. Disconnect negative battery cable.
2. Remove the radio control head, following the directions in the Service Manual, Section 8C. This will allow access to the radio control head wiring.
3. Add 1K ohm, 1/2 watt resistors as shown in the illustration. The resistors are available from a local electronics supply store, such as *Radio Shack. The resistors should be connected to a 12 volt ignition-switched circuit. For 1991 to 1993, there is an auxiliary power pickup in the console. For 1990, ignition circuit number 300 should be used. See Section 8A for wiring details.
4. Reinstall the radio, then reconnect negative battery cable. Clear the CCM DTC's as shown in Section 8D, and verify proper operation.
If further information is needed, contact the Corvette Action Center at 1-800-457-8388. Hours of operation are 6:00 a.m. to 4:30 p.m. Central Time, Monday to Friday.
"We believe this source and their equipment to be reliable. There may be additional manufacturers of such equipment. General Motors does not endorse, indicate any preference for or assume any responsibility for the products or equipment from this firm or for any such items which may be available from other sources."
Here is the TSB: http://www.corvetteforum.net/c4/dave8476/index4.shtml
03-25-2016, 05:34 PM
#11
Instructor
My 93 was lighting the SYS last fall. I had had it about 9 months at that time and it had an aftermarket head unit. I thought it strange that it took it this long to show up. My battery was doing strange things and I thought maybe it was loose terminals. I tightened those up and put it on the charger and that seemed to fix it. Several weeks later the battery left me high and dry away from the house. Got a new battery and that was that. This fix came to me from using search on CF.
