Circuit Description
The digital radio antenna is connected to the digital radio receiver (DRR) by 2 coax cables. One coax carries the satellite signal, the other coax carries the terrestrial signal. The antenna cable for the satellite antenna also provides a path for D.C. current for powering the antenna.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC B1259 Antenna Ground Circuit
Conditions for Running the DTC
This test is run every 300 milliseconds.
Conditions for Setting the DTC
The DRR detects an antenna fault.
Action Taken When the DTC Sets
The radio displays "No XM Signal."
Conditions for Clearing the DTC
| • | The condition must be corrected. |
| • | The DTC clears after 100 malfunction free ignition cycles. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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Early design modules support the mV reading while later design modules support the mA reading.
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Due to current limiting capabilities in the module, an antenna cable shorted to ground could still show 1200-1800 mV.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Schematic Reference: Radio/Audio System Schematics | ||||
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information |
With a scan tool, observe the digital radio antenna in the digital radio receiver (DRR) data list. Does the scan tool indicate that the digital radio antenna is within the specified range? | 1200-1800 mV or 42-118 mA | Go to Step 3 | Go to Step 4 | |
Test the antenna cables for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 10 | Go to Step 8 | |
4 |
Does the voltage measure within the specified range? | 4.5-5.5 V | Go to Step 5 | Go to Step 6 |
5 | Test the antenna cables for an open or a high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 10 | Go to Step 8 |
6 | Inspect for poor connections at the DRR. 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 DRR. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement? | -- | Go to Step 10 | -- |
8 | Inspect for poor connections at the digital radio 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 9 |
9 | Replace the digital radio antenna. Refer to Digital Radio Antenna Replacement . Did you complete the replacement? | -- | Go to Step 10 | -- |
10 |
Does the DTC reset? | -- | Go to Step 2 | System OK |
