Service Information

Cruze

DTC B1259

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 Descriptor

DTC B1259 02: Aerial 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 Aerial 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.

The Digital Audio Broadcast (DAB) radio receiver receives a digital radio signal via the digital radio aerial. This signal is passed to the DAB module through the digital radio aerial 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 aerial 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

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

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 .

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

Ignition OFF, disconnect the digital audio aerial coax from the digital audio broadcast module. Connect the EL-48028 to the radio.
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.

Ignition OFF, reconnect the aerial coax to the radio, disconnect the digital radio aerial coax from the T4H digital radio aerial.
Ignition ON, test for 4.5-5.5 V between the aerial coax centre terminal and the coax outer shield.

⇒	If not within the specified range, replace the aerial coax.

If all circuits test normal, replace the T4H digital radio aerial.

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