Circuit Description
The cellular antenna is connected to the vehicle communication interface module (VCIM) with a RG-58 coax cable. The VCIM polls the data from the cellular antenna once every second.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC B2470 Cellular Phone Antenna Circuit Malfunction
Conditions for Running the DTC
| • | The ignition must be in the RUN or ACC position. |
| • | The system voltage is at least 9.5 volts and no more than 15.5 volts. |
| • | All the above conditions are present for greater than 1 second. |
Conditions for Setting the DTC
| • | The VCIM does not detect the presence of a cellular antenna. |
| • | All the above conditions are present for greater than 1 second. |
Action Taken When the DTC Sets
| • | The OnStar® status LED turns red. |
| • | The vehicle is unable to connect to the OnStar® Call Center. |
Conditions for Clearing the DTC
| • | The VCIM detects the presence of a cellular antenna. |
| • | A history DTC clears after 50 malfunction-free ignition cycles. |
| • | The VCIM receives the clear DTC command from the scan tool. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
This step tests the condition of the cellular antenna.
-
This step tests the condition of the cellular antenna coax and for proper ground of the cellular antenna.
Step | Action | Value | Yes | No |
|---|---|---|---|---|
Schematic Reference: OnStar Schematics Connector End View Reference: Cellular Communication Connector End Views | ||||
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | |
Inspect the cellular antenna and cellular antenna coupling assembly for damage. Is the antenna assembly damaged? | -- | Go to Step 7 | Go to Step 3 | |
|
Important: The vehicle may be equipped with sectioned coax. Test each section and replace only the faulty section, not the entire length of coax.
Does the meter read out of limits? | -- | Go to Step 4 | Go to Step 5 | |
4 |
Does the resistance measure greater than the specified value? | 1 ohms | Go to Step 8 | Go to Step 6 |
5 | Inspect for poor connections at the harness connector of the VCIM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | -- | Go to Step 10 | Go to Step 9 |
6 | Inspect for poor connections at the harness connector of the cellular antenna. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | -- | Go to Step 10 | Go to Step 7 |
7 | Replace the cellular antenna. Refer to Cellular Communications/Digital Radio Antenna Replacement . Did you complete the replacement? | -- | Go to Step 10 | -- |
8 | Replace the cellular antenna coax. Did you complete the replacement? | -- | Go to Step 10 | -- |
9 | Replace the VCIM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | -- | Go to Step 10 | -- |
10 |
Does the DTC reset? | -- | Go to Step 2 | System OK |
