Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
DTC Descriptors
DTC B1259 02: Antenna Ground Circuit Short to GroundDTC B1259 05: Antenna Ground Circuit Short to Battery or Open
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Left Audio Signal (+) | 1 | 1 | 1 | -- |
Right Audio Signal (+) | 2 | 2 | 2 | -- |
Audio Common (-) | 3 | 3 | 3 | -- |
Digital Radio Antenna Coax | B1259 02* | B1259 05* | B1259 05* | -- |
1. No or distorted audio from left side speakers when listening to digital radio 2. No or distorted audio from right side speakers when listening to digital radio 3. No or distorted audio from all speakers when listening to digital radio *. Poor or no digital radio reception | ||||
Circuit/System Description
The digital radio receiver (DRR) receives XM satellite radio signals via a digital radio antenna located on the outside of the vehicle. The signal is passed to the DRR through digital radio antenna coax. From the DRR, one audio common (-) and separate left and right audio signals (+), are sent to the radio. The radio processes these signals and passes the audio to the appropriate speakers or audio amplifier.
Diagnostic Aids
When diagnosing digital radio concerns, the vehicle should be located outside with an unobstructed view of the southern sky to ensure proper reception of the satellite signal. Reception may limited, intermittent or not possible inside structures or under heavy cover.
Conditions for Running the DTC
| • | Radio ON. |
| • | Battery voltage must be between 9-16 volts. |
Conditions for Setting the DTC
B1259 02
The DTC will set when the DRR detects a short to ground in the antenna ground circuit.
B1259 05
The DTC will set when the DRR detects a short to voltage or an open/high resistance in the antenna ground circuit.
Actions Taken When the DTC Sets
| • | Digital radio reception may be poor or not available. |
| • | The radio displays "No XM Signal" or "Check Antenna". |
Conditions for Clearing the DTC
| • | The condition responsible for setting the DTC no longer exists. |
| • | A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred. |
Reference Information
Schematic Reference
Radio/Navigation System Schematics
Connector End View Reference
Description and Operation
Radio/Audio System Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Special Tools
EL-48028 Digital Radio Test Antenna
Circuit/System Verification
With the vehicle outside in an area with an unobstructed view of the southern sky, tune to XM. Verify XM reception is clear and the No XM Signal message is not displayed on the radio.
Circuit/System Testing
- Ignition OFF, disconnect the antenna coax from the DRR. Connect the EL-48028 to the DRR.
- Ignition ON, radio tuned to XM, verify verify DTC B1259 is not set as current.
- Ignition OFF, reconnect the antenna coax to the DRR, disconnect the digital radio antenna coax from the digital radio antenna.
- Ignition ON, test for 4.5-5.5 volts between the antenna coax center terminal and the coax outer shield.
- If all circuits test normal, replace the digital radio antenna.
| ⇒ | If the DTC is current, replace the DRR. |
| ⇒ | If not within the specified range, replace the antenna coax. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for DRR replacement, setup, and programming |
