My ONSTAR module did not work from factory. Module was replaced. Then antenna code B2470-04 came up when diag performed. Dealer replaced antenna. Code still comes up

Question edited for a lot more clarity.
Question moved to model category.

It is located under the radio.

https://www.google.com/search?q=2008+GMC+Yukon.+OnStar+module+location

Video shows a Silverado

Could be either one, but I would call Onstar tech support before doing anything. A dealer can probably figure out what's wrong in a hurry.

I 'll attempt. 3 places I have found onstar on GM vehicles. Older cars, you have to pull the dash to access them, Not yours. Next is under the dash in front of the center console. Still a pain to access, just to even unplug. Next is in the trunk, on the drivers side behind the carpet. Easy to recognize. One or two plugs and an antenna wire. I haven't eve replaced one. But disconnected many because they will kill data lines/ other computers. Just shorted out.

Did you put PATS transceiver module out of old steering into your replacement column ?
The transceiver module communicates with the encoded ignition key. This module is located behind the steering column shroud and contains an antenna connected to a small electronics module. During each vehicle start sequence, the transceiver module reads the encoded ignition key identification code and sends the data to the instrument cluster.
Other wise you'll have to take to the dealer to be reset , can only be done with dealer scan tool .

P70496 This is not a code . Has nothing to do with emission's .Now P0496 does P0496
Evaporative Emission (EVAP) System Flow During Non-Purge

Purge solenoid is probably bad .
Automotive Evaporative Emissions Part One

B2470
Cellular Phone Antenna Circuit Malfunction
VCIM
DTC B2470
DTC B2470 04: Cellular Phone Antenna Circuit Malfunction Open Circuit
The cellular antenna is connected to the communication interface module (CIM) with a RG-58 coax cable. The CIM polls the data from the cellular antenna once every second.
Circuit/System Testing
Ignition OFF, disconnect the cellular antenna coax from the CIM module and the cellular antenna.
Ignition ON, test for less than 1 volt between the antenna coax center terminal and ground.
? If greater than the specified range, replace the antenna coax.
Ignition ON, test for less than 1 volt between the antenna coax outer shield and ground.
? If greater than the specified range, replace the antenna coax.
Test for infinite resistance between the antenna coax center terminal and ground.
? If less than the specified value, replace the antenna coax
Test for infinite resistance between the antenna coax outer shield and ground.
? If less than the specified value, replace the antenna coax
Test for less than 5 ohms at the cellular antenna coax center terminal from end to end.
? If greater than specified value, replace the cellular antenna coax cable.
Test for less than 5 ohms at the cellular antenna coax outer shield from end to end.
? If greater than specified value, replace the cellular antenna coax cable.
Test for infinite resistance between the antenna coax center terminal and the outer shield.
? If less than specified value, replace the cellular antenna coax cable.
If coax cable tests normal, replace the cellular antenna.
Clear the DTCs and operate the vehicle within the conditions for running the DTC. Verify DTC B2470 does not set.
? If the DTC sets, replace the CIM.

You can but the dealer will still have to initialize it to work with your car.

Hi there:
Almost directly behind the on-star button behind center of dash. Just keep in mind that the Vehicle Communication Interface Mocule (VCIM or VCM aka OnStar Module) has a specific set of unique numbers that be the module to each vehicle. These numbers, the 10 digits station identification and the 11 digits electronic serial number, are used by Natural Cellular Network and OnStar to identify the specific vehicle. Because these numbers are tied to the VIN (Vehicle Identification Number) of the vehicle, you must never exchange these parts with those of another vehicle.

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This code indicates an error or fault in the powertrain control module memory. A common procedure known as memory flashing is performed at the dealer. The vehicle's computer (powertrain control module) memory is erased, then replaced with an updated version of the previous driveability program. If the powertrain control module doesn't store the program, then a replacement module would be the next likely service.

Make sure the technician scans the module for codes before replacing. If the antenna is at fault, the module will set the specific code for the antenna.
Did he explain why the module would need to be replaced?
Let me know.
Regards,

The OnStar module is under the rear seat, passenger side. You should be able to just pull the connectors out of the module. Just the rectangular ones.

The dealer is thinking about the power amplifier for the Bose radio system. That's in the fender at the right rear of the car, but that's not the issue here.