$EEHack Read Failure Every Time?

[spfautsch]

I can tell you from experience the CCM starts talking when you open a door. I've been using a FTDI board hanging on the passenger's side of the console with rx/tx leds on it for several years, and when mine's not connected to my usb hub the leds start flashing away when I open the passenger side door.

The PKE coming into range most likely causes chatter on the aldl - mine doesn't work correctly so I have no idea.

[steveo]

there must be command sets for the ccm has anyone seen any documentation for them? a .ds file or something?

[NomakeWan]

Here's the DS file for the 1994 Corvette CCM: http://gearhead-efi.com/gearhead-efi/def/aldl/A239.DS

I'm currently mid-project on a drivetrain swap for a GTR which is on jackstands in my driveway, so my Corvette is in the driveway under a car cover. I won't be able to play around with it until this Sunday at the earliest. Might take until the weekend after, we'll see.

[steveo]

well i don't see much good there to help with our comms but why dont we add that to the definition for the next version.... i did write multiple device support into EEHack, and it's barely been tested. there is some cool stuff in there. i wonder if it responds to any of the other commands we usually use for reflash, read ram, etc?

[NomakeWan]

Good question! I have some serial data apps on my laptop so I can try talking manually once I'm able to mess with the car again. I've done it just fine on Subarus and Nissans, not sure how well it'll work on a GM but I'll give it a whirl once I can.

If we're adding definitions, here's a list of what filenames refer to what:
http://www.totalcardiagnostics.com/p...efinitions.htm

And here's the database of the actual GM data stream definitions once you know what's what:
http://gearhead-efi.com/gearhead-efi/def/aldl/

For the '94-'95 Corvette, though, these are what I've found:

A175 ABS/ASR 1992-1994 CORVETTE
A223 1994-1995 CORVETTE AUTOMATIC TRANSMISSION
A239 1994 CORVETTE CCM
A242 1994-1995 SIR/SRS
A275 1994-1995 CORVETTE MANUAL TRANSMISSION
A288 ABS/ASR 1995 CORVETTE
A297 1995 CORVETTE CCM

Unfortunately I couldn't locate a definition for the HVAC system for the Y-body, or the passive keyless entry system. Actually kinda neat though, the ABS/ASR unit can tell you how many lateral Gs your car is pushing!

EDIT: Having a look at the service manual for the 1994 and 1995 Corvette, the HVAC is indeed tied into Pin 9 on the ALDL connector with everything else, which jives with it blinking when I try to connect anything to the line and shut everyone up. PKE however is on a totally different pin, same with FX3. Odd that I can't find a reference to Y-body C68 HVAC in the Data Stream definitions.

[spfautsch]

Actually kinda neat though, the ABS/ASR unit can tell you how many lateral Gs your car is pushing!

Interesting. I have to wonder how accurate the 90's era solid state accellerometers are.

EDIT: Having a look at the service manual for the 1994 and 1995 Corvette, the HVAC is indeed tied into Pin 9 on the ALDL connector with everything else, which jives with it blinking when I try to connect anything to the line and shut everyone up. ... Odd that I can't find a reference to Y-body C68 HVAC in the Data Stream definitions.

This is just a WAG, but I'd think the C68 climate control box might be a bus listener only and probably does not have the capability to transmit.

[NomakeWan]

I work with 90s era hall-effect pendulum accelerometers actually! They’re...decent, if they’ve survived to the present day without their swing arms bending or their capacitors spewing their contents into the PCB. A little slow to react due to their mechanical nature but considering the speed of the computer interpreting them it’s not much of a bottleneck. That said, switching it to a modern MEMS version can improve performance depending on how the data is used. I haven’t tested ASR on the C4 yet but on a Skyline GT-R switching to MEMS has a noticeable improvement in AWD performance.