Flashing "SYS" indicator next to tach

[Brian Smith]

Just got my 1993 LT1 out of the paint shop and the display, where the fuel mileage data etc. is displayed, has started flashing "Sys" while running. Once it starts flashing it flashes once per second for three cycles and then the normal display starts back up and at an undetermined interval it will start again with the same rep rate.

The only thing that has changed was, while the car was being painted the painter located the driver door security electrical pickup (coil?) that goes on the door key lock cylinder post. It was dangling down in the door somewhere. It is now back where it belongs and plugged into the appropriate connector. Also found the Driver PKE door mounted antenna connector dangling and re-attached it to the proper connector on the antenna.

Eight months ago I replaced the missing fob from that outfit down in Austin Texas and tried to configure the PKE system to work properly. It never did work properly and saw some posting on the internet compaining about that firm and their inability to do the right thing. Now given that I approach the car from the drivers side and now know the receiving antenna was disconnected and the coil on the lock wasn't in place maybe it was working as well as one could expect.

I know I have many variables at play here but the starting point is to determine what triggers that "Sys" message next to the tach. I reviewed the factory manual at some length but as you guys know there is much data there and it is easy to chase the wrong rabbit down the wrong hole.

I'm not sure any of that other mess I mentioned has a role in all this but thought I would mention it and ask if any of you old technical hands have tripped across this before. Thanks in advance for your kind consideration.;help

 

[Stuart]

Ccm

The glove box manual for my 93 on page 120 says:

"The Central Control Module (CCM) controls several electronic systems on your Corvette. SYS will flash three
times every 15 seconds on the display near the fuel gage if there is a problem with one of the CCM-controlled
systems. Have your vehicle checked by a Chevrolet dealer if SYS keeps appearing."

"If the SECURITY light flashes at the same time the SYS flashes on the instrument panel a problem has been
detected in your thet deterrent system. If this occurs, have your vehicle serviced."

Did you notice SECURITY flashing too? That would lead me to believe that your reconnected lock related stuff could be causing the SYS light to flash.

I'm not much of a mechanic but I leafed through the Service Manual and found a couple things of interest.
You can enter the diagnostic mode of the CCM by grounding pin "G" of the data link connector.
Looking through the possible codes, I suspect that your reconnected door lock coil is causing the error. The manual says that "The courtesy lamp relay coil circuit is completed by the CCM when it receives a courtesy lamps "ON" request from any number of different inputs (door lock switches, door ajar switches). Codes 24 and 25 indicate a problem with the courtesy lamp relay circuit.

 

[Rabbit]

May just be a weak battery?????

 

[tmkassin]

Do the paperclip thing and check for codes. There are three computers so make sure you are reading the codes correctly.

 

[Brian Smith]

Well, I disconnected the battery and waited long enough to put one door panel on and reconnected and drove the car and the symptoms are gone. I imagine that there was some sort of check the CPU did upon start up (initial) and saw the connectors to the two sensors were not responding and logged a fault. Since I reconnected those two sensors later it still had the fault set into the CPU. Power down of the CPU long enough to flush the logged error let him run with the "Sys" flashing display. Thanks guys!

 

[Schrade]

Well, I disconnected the battery and waited long enough to put one door panel on and reconnected and drove the car and the symptoms are gone.

Sounds great!

(it did go closed loop - right?)

edit:
and then again, it might not be necessary for it to go closed loop on a SYS error, for it to register again...

 

[Brian Smith]

Closed loop as in fuel mapping and CPU learning? It did seem to do the usual "idle a couple hundred RPM fast" for about five operating minutes.

I locked the car at church last night using the driver door panel switch and after used the key to unlock to drivers door and the alarm faulted and the horn honked until I put the key in the ignition.Of course the fob was at home.

Am currently reviewing the PKE programming lrule logic, capabilities and instructions in hopes that the fob problem I mentioned earlier is a brain cell problem (on my part) and not an issue with the fob.

 

[Brian Smith]

Update: Used my DVM and evaluated the key fob and the it's battery (instead of 3 volts) was down to .12 volts. Replaced it and the PKE works as designed. That is an impressive piece of design work. It has never worked in the year I've owned the car and now it does.

This is my first Vette and I am more impressed with ALL the unique design touches that were incorporated in it and the consideration the engineers had for the driver!