For 1990-2009 cars

### 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.

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
B+ Voltage | -- | 1 | -- | --
Left Audio Signal (+) | 2 | 2 | 2 | --
Right Audio Signal (+) | 3 | 3 | 3 | --
Audio Common Signal (-) | 4 | 4 | 4 | --
Digital Radio Antenna Coax | B1259 02 | B1259 05 | B1259 05 | --
Ground | -- | 1 | -- | --
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 4. No or distorted audio from all speakers when listening to digital radio

### 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, 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 be limited, intermittent, or not possible inside structures or under heavy cover.

### Reference Information

#### Schematic Reference

Radio/Navigation System Schematics

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

Radio/Audio System Description and Operation

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### Scan Tool Reference

Control Module References for scan tool information

#### Special Tools

EL-48028 Digital Radio Test Antenna

### Circuit/System Verification

1. Tune to a strong AM or FM station and verify each speaker is producing clear and even sound, with no distortion.

⇒ | If any speaker is not producing sound or the sound produced is distorted, refer to Speaker Malfunction.

2. 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.

⇒ | If the No XM Signal message is displayed or XM reception is poor, refer to Digital Radio Antenna Circuit Malfunction.

3. Radio tuned to XM, use the radio balance function to transfer audio between the left and right side of the vehicle. Verify clear and even sound is heard from each side of the vehicle.

⇒ | If either side of the vehicle is not producing sound or the sound produced is distorted, refer to Digital Radio Signal Circuit Malfunction.

### Circuit/System Testing

#### Digital Radio Antenna Circuit Malfunction

1. Ignition OFF, disconnect the digital radio antenna coax from the digital radio receiver (DRR). Connect the EL-48028 to the DRR and move the vehicle outside in an area with an unobstructed view of the southern sky, tune to XM.
2. Ignition ON, radio tuned to XM, verify XM reception is clear and uninterrupted.

⇒ | If reception is not clear, replace the DRR.

3. Ignition OFF, reconnect the antenna coax to the DRR, disconnect the digital radio antenna coax from the digital radio antenna.
4. Ignition ON, test for 4.5-5.5V between the antenna coax center terminal and the coax outer shield.

⇒ | If not within the specified range, replace the antenna coax.

5. If all circuits test normal, replace the digital radio antenna.

#### Digital Radio Output Circuit Malfunction

1. Ignition OFF, disconnect the X2 harness connector at the radio.
2. Ignition ON, radio ON and tuned to XM, test for a varying mV AC voltage reading between the following signal circuit terminals listed below and ground.

• | Left audio signal (+) - terminal 1

• | Right audio signal (+) - terminal 2

• | Audio common signal (-) - terminal 9

⇒ | If the varrying mV A/C voltage reading is not present, test the signal circuit for a short to voltage, short to ground, or an open/high resistance. If the circuit tests normal, replace the DRR.

3. If all circuits test normal, test or replace the radio.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Digital Radio Antenna Replacement

• | Digital Radio Antenna Cable Replacement

• | Control Module References for DRR and Radio replacement, setup, and programming