DTC B1259
Diagnostic Instructions
DTC Descriptor
| DTC B1259 02: Antenna Ground Circuit Short to
Ground |
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.
Conditions for Running the DTC
The ignition is ON.
Conditions for Setting the DTC
B1259 02
The Digital Audio Broadcast module detects a short to ground in the
antenna circuit.
Action Taken When the DTC Sets
The radio no longer emits audio when on digital audio broadcast
radio.
Conditions for Clearing the DTC
| • |
A current DTC will clear when
the conditions for setting the DTC are no longer present.
|
| • |
A history DTC clears after 100
malfunction-free ignition cycles. |
Diagnostic Aids
When diagnosing digital radio concerns, the vehicle should be
located outside with an unobstructed view of the sky to ensure
proper reception of the digital radio signal. Reception may
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
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 sky, tune to Digital Audio.
Verify reception is clear and audio is emitted from the A11
radio. |
Circuit/System Testing
| 1. |
Ignition OFF, disconnect the
digital audio antenna coax from the digital audio broadcast module.
Connect the EL-48028 Digital Radio Test Aerial to
the radio. |
| 2. |
Radio ON, tuned to Digital
Audio, verify DTC B1259 is not set as current. |
| ⇒ |
If the DTC is current, replace the A12 digital
radio receiver. |
| 3. |
Ignition OFF, reconnect the
antenna coax to the radio, disconnect the digital radio antenna
coax from the T4H digital radio antenna. |
| 4. |
Ignition ON, test for
4.5–5.5 V 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 T4H digital radio antenna. |
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic
procedure.
Control Module References for Radio and Digital Audio Broadcast
replacement, setup, and programming
|
