Circuit Description
The cellular portion of the cellular and navigation antenna is connected to the vehicle communication interface module (VCIM) with a RG-174 coax cable. The VCIM polls the data from the antenna once every second.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC B2470 Cellular Phone Antenna Circuit
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 the 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 the cellular and navigation 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 checks the condition of the cellular and navigation 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 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information |
Inspect the cellular and navigation antenna assembly for damage. Is the antenna assembly damaged? | -- | Go to Step 7 | Go to Step 3 | |
|
Important: 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 in Wiring Systems. 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 and navigation antenna. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 10 | Go to Step 7 |
7 | Replace the cellular and navigation antenna. Refer to Cellular and Navigation Antenna Assembly 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 in Computer/Integrating Systems 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 |
