billschroeder5842

Hey all, can I get a couple of hints to make the CCM diagnostic run on my '91 ZR1 please?

I have a hand held unit (a left over from my '82 with the OBD1 connection) and when plug it in, I get the full on ECM treatment with the flashing codes on the DIC. Currently I'm getting repeating 1-2 so I'm good.

I have tried to jump the grounds from the A to G on the terminal with a paper clip and with no luck. I don't have anything wrong with the car, I just want to learn how the CCM diagnostic operates. The CCM read out looks very cool and has a lot more information.

So, am I just doing it wrong on the paper clip jump on the terminal? Does the car read both ECM and CCM depending on the ground or does it read only one or the other?

Thanks!

ChumpVette

That is incorrect. You go into module 4 and it gives you the ECM trouble codes for L98LT1 or LT5. The service manual even gives you a list of codes for whatever ECM is present in the car.

ChumpVette

What year(s)?

And to specify, year of manual, page and color of the manual (red or white)?

*Update* it appears you are working out of a 93 FSM. I see the statement you mention about the LT5 on 8D-9. Which is odd, as the 90, 91, 92, includes LT5 ECM diagnostics in the CCM module 4. Then the 94 and 95 books make no mention of the LT5 ECM being excluded specifically like the 93 book.

For the OP with his being a 91, he will be able to access it through the CCM.

WVZR-1

I've a Tech1 so I've never even attempted to do the IP DISPLAY but it does seem ODD that '93 MY wouldn't be available. I don't have a '93 MY to try either. Maybe the 1st year for EGR LT5 it wasn't made available or perhaps the ZR-1/LT5 cluster wouldn't accommodate the change.

Here's the excerpt from the FSM that IHBD has mentioned. It does state that so if you've a '93 ZR-1/LT5 how about giving it a try.

billschroeder5842

Both my ECM "Flash" and CCM "codes" work on my '91.

After my brain fart cleared, I was able to the the CCM codes and diagnostics to work. It was my error as I was not "pushing" my wire far enough in the terminal-- I was simply being too ginger with it.

Once jumped the CCM codes came on and work exactly as outlined the the FSM. Mercifully I saw only "C12" and "---" for all modules and I cleared all the .7s for good measure.

I do have a "history" marker of 1-3 for the INFL REST, but that is a different story