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 |
|---|---|---|---|---|
B+ Voltage | -- | 1 | -- | -- |
Ground | -- | 1 | -- | -- |
Left Audio Signal (+) | 2 | 2 | 2 | -- |
Left Audio Signal (-) | 2 | 2 | 2 | -- |
Right Audio Signal (+) | 3 | 3 | 3 | -- |
Right Audio Signal (-) | 3 | 3 | 3 | -- |
Digital Radio Antenna Coax | B1259 02 | B1259 05 | B1259 05 | -- |
1. No communication with DRR/XM not available 2. No or distorted audio from left side speakers when listening to digital radio 3. No or distorted audio from right side speakers when listening to digital radio | ||||
Circuit/System Description
The digital radio receiver (DRR) receives an XM satellite radio signal via the digital radio antenna. This signal is passed to the DRR through the digital radio antenna coax. The DRR sends a varying AC mV signal through separate left and right audio circuits (+ and -) to the radio. The voltage amount and rate of change is dependent upon the type of signal being received. The radio then processes these signals and passes the audio to the appropriate speakers or 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.
- Radio ON, tuned to XM, verify DTC B1259 is not set.
- 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 V 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 set, 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 |
