Digital Radio Poor or No Reception
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Digital Radio Poor or No Reception
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Diagnostic Fault Information
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Circuit
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Short to Ground
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Open/High Resistance
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Short to Voltage
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Signal Performance
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B+ Voltage
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-
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1
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-
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-
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Left Audio Signal (+)
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2
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2
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2
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-
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Left Audio Signal (-)
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2
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2
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2
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-
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Right Audio Signal (+)
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3
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3
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3
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-
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Right Audio Signal (-)
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3
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3
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3
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-
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Digital Radio Antenna Signal
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B1259 02
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4
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4
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-
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Ground
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-
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1
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-
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-
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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.
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Circuit/System Description
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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 Alternating Current (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.
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
Scan Tool Reference
Control Module References
for scan tool information
Special Tools
EL-48028 Digital Radio Test Antenna
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Circuit/System Verification
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1.
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Tune to a strong AM or FM station and verify each speaker is producing clear and even sound, with no distortion.
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2.
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If any speaker is not producing sound or the sound produced is distorted, refer to
Speaker Malfunction
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3.
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With the vehicle outside in an area with an unobstructed view of the southern sky, tune to Digital Audio. Verify reception is clear.
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4.
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If reception is poor, refer to Digital Radio Antenna Circuit Malfunction.
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5.
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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.
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6.
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If either side of the vehicle is not producing sound or the sound produced is distorted, refer to Digital Radio Signal Circuit Malfunction.
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Digital Radio Antenna Circuit Malfunction
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1.
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Ignition OFF, disconnect the antenna coax from the A12 Digital Radio Receiver Control Module. Connect the EL-48028to the A12 Digital Radio Receiver Control Module.
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2.
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Ignition ON, radio tuned to digital radio, verify reception is clear and uninterrupted.
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3.
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If reception is not clear, replace the A12 Digital Radio Receiver Control Module.
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4.
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Ignition OFF, reconnect the antenna coax to the A12 Digital Radio Receiver Control Module, disconnect the digital radio antenna coax from the T4H Digital Radio Antenna.
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5.
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Ignition ON, test for 4.5-5.5 V between the antenna coax center terminal and the coax outer shield.
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6.
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If not within the specified range, replace the antenna coax.
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7.
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If all circuits test normal, replace the T4H Digital Radio Antenna.
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Digital Radio Output Circuit Malfunction
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1.
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Ignition OFF, disconnect the X1 harness connector at the A11 Radio.
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2.
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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.
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•
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Left audio signal (+) terminal 22
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•
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Left audio signal (-) terminal 8
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•
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Right audio signal (+) terminal 21
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•
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Right audio signal (-) terminal 7
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3.
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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 Control Module.
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4.
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If all circuits test normal, replace the A11 Radio.
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Perform the
Diagnostic Repair Verification
after completing the diagnostic procedure.
Control Module References
for radio and digital audio broadcast module replacement, setup and programming
