"sys"
Le Mans Master
Joined: Jan 2006
Posts: 5,621
Likes: 206
From: Orlando FL
I t can mean the a code has been stored by the CCM in module 1. But in most cases it means the battery is getting weak and the CCM is not liking it. If no code is stored, most likely the battery should be replaced. Sometimes as the battery charges after the start, the SYS light will go off. 
Does it stay on all the time..or not?
Does it stay on all the time..or not?
Melting Slicks
Joined: Dec 2004
Posts: 2,522
Likes: 763
My 1990 coupe was doing the blinking "sys" from the moment I drove it away from the previous owner's driveway. My battery eventually went dead and I replaced it with a new one. Months later, the engine would stall out at the most unpredictable times. Months later, it got so bad that the engine would run only 10 minutes and cut off and wouldn't start again until it was completely cooled.
I replaced the igition coil, distributor cap and rotor, fuel filter and fuel pump--all on the advice of backyard mechanics and CF members.
I finally gave up and had the car towed to a mechanic. He determined that the engine computer was malfunctioning when the engine was warm. As a test, he put the computer in a freezer for a couple of hours. He put the computer back in and the engine ran perfectly for 45 minutes and then shut off. His $4,000 diagnostic computer had already told him the computer was malfunctioning. He said the computer was turning on some items after the car was parked and that was running my batteries down. I had installed a third battery before the computer was replaced. Just sitting in my driveway, the battery would go dead in just four or five days. I had to keep the negative cable disconnected.
The mechanic replaced the computer. Unfortunately, he replaced the computer with one from a junkyard. That computer lasted a year and I replaced it with remanufactured one. That one has last one and a half years. On hot days, I park the car in my driveway and keep the hood up for an hour to allow the engine and computer to cool off.
A GM mechanic told me that some of the computers are prone to developing short circuits when the engine's heat softens a soldered connection in the computer. Another mechanic told me to get my next computer at NAPA. I haven't seen the flashing "sys" light in nearly three years. But I did replace the alternator and serpentine belt last week. No more reman. alternators for this Corvette.
I replaced the igition coil, distributor cap and rotor, fuel filter and fuel pump--all on the advice of backyard mechanics and CF members.
I finally gave up and had the car towed to a mechanic. He determined that the engine computer was malfunctioning when the engine was warm. As a test, he put the computer in a freezer for a couple of hours. He put the computer back in and the engine ran perfectly for 45 minutes and then shut off. His $4,000 diagnostic computer had already told him the computer was malfunctioning. He said the computer was turning on some items after the car was parked and that was running my batteries down. I had installed a third battery before the computer was replaced. Just sitting in my driveway, the battery would go dead in just four or five days. I had to keep the negative cable disconnected.
The mechanic replaced the computer. Unfortunately, he replaced the computer with one from a junkyard. That computer lasted a year and I replaced it with remanufactured one. That one has last one and a half years. On hot days, I park the car in my driveway and keep the hood up for an hour to allow the engine and computer to cool off.
A GM mechanic told me that some of the computers are prone to developing short circuits when the engine's heat softens a soldered connection in the computer. Another mechanic told me to get my next computer at NAPA. I haven't seen the flashing "sys" light in nearly three years. But I did replace the alternator and serpentine belt last week. No more reman. alternators for this Corvette.
