I installed a DIC overhead console from a 2001 Monte Carlo SS into my '98 cav, Got everything wired up and mounted, the sunroof switch works Homelink works, compass and temp work (for 10 seconds after the car is turned on then the compass freezes on its current location and the temp displays --*) None of the trip/Econ is working yet, cant seem to get the Class 2 serial data to read from the DLC. Athough my J2534 Pass-through reads and responds to the PCM, ABS, and IPC on the Class 2 data bus without issues. I wouldn't think that GM would put a check vin authentication on the DIC like Class 2 serial radios would they? I know 98 didn't have a BCM but that should not make a difference as the trip/ econ should only need to read VSS, MAP, and maybe Calc Load from the PCM. Is it possable that the Monte Carlo relies on a class 2 serial radio to provide the functions of the DIC? But then why won't the Compass or Ambient air temp work for more than 10 seconds? They have their own sensors separate from the PCM and shouldn't rely on any TX/RX data sent over a serial bus. Anyone have any ideas? I would like to get full functionality out of it.

Hope you get this figured out bro. Looks like a great addition!



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Hum, Well I installed a DIC overhead console in my old 2002 s-10 and i do remeber that I had to use a DATA2 wire from the double din harness. And the VSS from the BCM before everything worked ok.

Let us know if you get it all working properly. I like this idea and would be willing to do it.

2000+ started class 2 data wiring, your pre 2k shouldn't have any. I bet it's looking for class 2, sees it's not there, and then shuts down.




Your car may do 13 sec @ 103 mph, but my car does 146db @ 35 hz.

Hmm, this is something I've been thinking about for a while. I hope you get this working 100%

Lanman31337 - Cavfire wrote:2000+ started class 2 data wiring, your pre 2k shouldn't have any. I bet it's looking for class 2, sees it's not there, and then shuts down.

Actually Class 2 Serial was implemented in 1996 as part of the SAE J1850 VPW protocol required for OBD II on GM vehicles (J1850 - Defines a serial data protocol. There are 2 variants- 10.4 kbit/s (single wire, VPW) and 41.6 kbit/s (2 wire, PWM). Mainly used by US manufacturers, also known as PCI (Chrysler, 10.4K), Class 2 (GM, 10.4K), and SCP (Ford, 41.6K)), however in 2000 GM added additional class 2 modules to the subsystem such as the BCM and radio changing class 2 reference signaling. for instance in 1998 Class 2 would reference Various modes of operation from the PCM, IPC, ABS, and SRS modules which all communicate on a class 2 serial bus...

Mode $01 is used to identify what Powertrain information is available to the scan tool.

Mode $02 displays Freeze Frame data.

Mode $03 lists the emission-related "confirmed" diagnostic trouble codes stored. It displays exact numeric, 5 digit codes identifying the faults.

Mode $04 is used to clear emission-related diagnostic information. This includes clearing the stored pending/confirmed DTCs and Freeze Frame data.

Mode $05 displays the oxygen sensor monitor screen and the test results gathered about the oxygen sensor.

And so on...

Now GM had added Modes of operation in 2000 so the Class 2 sub system can acquire information from the BCM and radio. These modes may be $20, $21, $22, etc, $30, $31, $32, etc or $40, $41, $42, etc

What I think is going on is the Logic chip in the DIC is looking to communicate though another module such as the BCM or radio to handle the modes it needs to acquire through priority on another Module (Priority handling is the job of the of the IPC on a 1998 and the BCM on 2000+).

I have heard that removing the factory class 2 radio on some other GM vehicles inhibits other functions such as FOB programing and other convenience options...

I'm thinking I need to find a running Impala or Monte Carlo to scan and find where this thing is referencing it's mode of operation, because its obvious it does not read directly from the PCM...

I have a console from a 2000ish blazer ill hook it up to my cava and see what I find out

Looks great! I hope you get it working propely. Then post up a nice how-to for those of us that are to lazy to figure it out...

FZA wrote:I have a console from a 2000ish blazer ill hook it up to my cava and see what I find out

I was checking those out, I think the Blazer/ Jimmy/ Bravada DIC's have the same wiring as My 2000 Grand Prix GTP. Those require feeds from the VSS and the UART data from the PCM... The Monte Carlo/ Impala is different, as there is no connection to the VSS, just the Yellow wire which connects to the Class 2 Data link communications. I would like to know how the S-series DIC works in a J, if the Fuel/ Econ is even accurate... as it seems to me that those units would be VSS vs. MAP Precalc Logic. In other words would it still would show you BSFC (Brake Specific fuel consumption) for a 4300 vortec and not a 2200... Let me know what you find out FZA... I may just change this thing out in favor of the S-series DIC if that one actually works...