'95 Coupe with SYS flashing

lcollison said:

I pulled the codes by shorting pin 12 to pin 4. Got the following:


MODULE 1
C 13
11 13 (or maybe that's a H 13)?

My question is do I have a "DTC # 13" Bank #1 Heated Oxygen Censor #1 Circuit problem?

Or is it something else?

Click to expand...

Yes - it's an H 13.

According to my FSM (Section 8D-6), DTC 13 is "DIC Switch open or shorted to B+".

It's apparently happened before (hence the H13, which is a historical code, and the C indicates a current code).

From Section 8D-20 of the FSM,

The Driver Information Center switches circuit contains a number of resistors in series that create a voltage divider circuit. When a particular switch is pressed, the circuit resistance changes, and alters the voltage level at CCM terminal E11. By monitoring the voltage level at terminal E11, the CCM determines which switch was pressed and performs the desired function (ie switching the DIC display between fuel and gages, or between English and Metric, or one of the functions within a group).

DTC 13 will set when the CCM senses high voltage (> 5 Vdc) in CKT 1358 for longer than 3 seconds, and that will be considered an open or short to B+.

Additionally, SYS will begin flashing, and the DIC will no longer recognize switch presses.

Click to expand...

Has your Driver Information Center stopped responding to commands to change (like Instant Fuel Mileage to Avererage Fuel Mileage)? If not, then you probably have an intermittant problem.

I had the SYS flashing problem over the July 4 weekend. Here's the link to that thread ...

http://www.digitalcorvettes.com/forums/showthread.php?t=79357

Maybe some of the things I discovered will also help you in your quest to solve your problem.

Steven

I got the information I posted from my Factory Service Manual. I bought mine at Bloomington Gold in 2006, but they are commonly available on eBay, or you can order one from Helm Incorporated at the following link:

http://www.digitalcorvettes.com/forums/showthread.php?t=61402

http://www.helminc.com/helm/Result....dule=&mscsid=BJUVXMALDJKB9GQ0THUFJ5LAKTTP9VS4

Make sure if you buy them off eBay (or from some other seller) that you get both books. The final version has a red cover - the preliminary version has a white cover (I don't know how much changed between the two).

lcollison said:

Question - On these forums the DTC codes for a 1995 Vette shows a code 13 to be 'Bank #1 Heated Oxygen Sensor #1 Circuit'

Click to expand...

I'm assuming that you're talking about this thread ...

http://www.digitalcorvettes.com/forums/showthread.php?t=54543

(C4 Trouble Code list).

Those are the PCM (Powertrain Control Module) codes listed for the later C4's, and ECM codes for the earlier C4's. Those are codes that are set when the "Service Engine Soon" light is lit in the Idiot Light panel on the right side of the dashboard.

A flashing SYS light indicates a problem with the Central Command Module, and it has it's own set of codes, which are not listed in that thread (I guess I should transcribe 'em, and add it to the thread, shouldn't I?).

Clear as mud, right?

Let me know if you have any more questions.

Thanks,
Steven