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.
This diagnostic procedure supports the following DTC:
DTC B2470 Cellular Phone Antenna Circuit Malfunction
• | 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. |
• | The VCIM does not detect the presence of a cellular antenna. |
• | All the above conditions are present for greater than 1 second. |
• | The OnStar® status LED turns red. |
• | The vehicle is unable to connect to the OnStar® Call Center. |
• | 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. |
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: Refer to Entertainment/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 |