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 | -- |
Left Audio Signal (-) | 2 | 2 | 2 | -- |
Right Audio Signal (+) | 3 | 3 | 3 | -- |
Right Audio Signal (-) | 3 | 3 | 3 | -- |
Digital Radio Antenna Coax | B1259 02 | 4 | 4 | -- |
Ground | -- | 1 | -- | -- |
1. No communication with Digital Audio Broadcast module. 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. Poor or no reception with Digital Audio Broadcast. | ||||
Circuit/System Description
The Digital Audio Broadcast (DAB) radio receiver receives a digital radio signal via the digital radio antenna. This signal is passed to the DAB module through the digital radio antenna coax. The DAB module 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 amplifier.
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
- Tune to a strong AM or FM station and verify each speaker is producing clear and even sound, with no distortion.
- With the vehicle outside in an area with an unobstructed view of the southern sky, tune to Digital Audio. Verify reception is clear.
- A11 Radio tuned to Digital Audio, 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 any speaker is not producing sound or the sound produced is distorted, refer to Speaker Malfunction. |
| ⇒ | If reception is poor, refer to Digital Radio Antenna Circuit Malfunction. |
| ⇒ | 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
- Ignition OFF, disconnect the antenna coax from the A12 digital radio receiver. Connect the EL-48028 to the A12 digital radio receiver.
- Ignition ON, radio tuned to digital radio, verify reception is clear and uninterrupted.
- Ignition OFF, reconnect the antenna coax to the A12 digital radio receiver, disconnect the digital radio antenna coax from the T4H 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 T4H digital radio antenna.
| ⇒ | If reception is not clear, replace the digital radio receiver. |
| ⇒ | If not within the specified range, replace the antenna coax. |
Digital Radio Output Circuit Malfunction
- Ignition OFF, disconnect the X1 harness connector at the A11 radio.
- Ignition ON, radio ON and tuned to digital radio, test for a varying mV AC voltage reading between the following signal circuit terminals listed below and ground.
- If all circuits test normal, replace the A11 radio.
| • | Left audio signal (+) - terminal 22 |
| • | Left audio signal (-) - terminal 8 |
| • | Right audio signal (+) - terminal 21 |
| • | Right audio signal (-) - terminal 7 |
| ⇒ | If the varying mV AC voltage 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 A12 digital radio receiver. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Control Module References for radio and digital audio broadcast module replacement, setup, and programming
