Z51JEFF

I get this flashing at times but not constant.I checked for codes but none at present.Its been awhile since Ive used the A-B terminal trick but checked for codes and got a 12 which If I remember correctly is normal.Any clues?

mike100

SYS is a CCM issue. There is a separate way to read CCM codes- maybe? I can't recall. The only time I got the SYS message was when I forgot to reinstall the airbag fuse.

Phat98

Aftermarket radio?

94z07fx3

or low battery?

Z51JEFF

Stock stereo,Im leaning towards a battery problem.

wschmidt

Depending on what year you have you can short pins A to G (pretty sure this is the right lettering, its the top right to bottom left on the DLC) and read the codes out on the speedo. On mine, a 1993, I can read the CCM, ECM, and ASR system codes easily on the display instead of having to count SES light flashes when you short pins A and B.

RollaMo-LT4

If your still using the factory stereo, then my bet is on the battery also.

An SYS flashing every so often indicates an electrical issue, and the most likely cause is a low or almost dead battery.

I had that SYS flash every minute or so, and I knew my battery was questionable.
It would still start the car, but you could tell it wasn't turning it over very fast.
If it would have been the middle of winter or heat of summer, it probably wouldn't have had enough to turn the engine over.
I replaced the battery and the flashing SYS went away.

pcolt94

I agree with the battery theory, SYS comes and goes. If it is hot where you are and the battery is over 3 years old, it definitely might be a suspect as the cause.

I think most of us has gone thru this, me included.