U048A

Code

Generic U — Network/User

Invalid Data Received From Digital Disc Player/Changer Module C

Brand: Generic

Type: U — Network/User

Views: UK: 23 EN: 61 RU: 25

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Page language: EN

Faulty Digital Disc Player/Changer Module C (firmware or hardware failure)
Open, short or intermittent wiring/connectors on module power, ground or data lines
Poor or missing ground or low battery/unstable supply voltage to the module
Corrupted software or configuration mismatch after a module replacement or update
Bus communication errors (CAN/LIN/MOST) or missing termination
Electromagnetic interference or damaged bus transceiver

Use a scan tool to confirm U048A is present and view freeze frame/occurrence count
Check for other communication or audio-related DTCs
Visually inspect the disc player module connector for corrosion, bent pins, or moisture
Verify battery voltage and main fuses for the audio system with engine off and running
Check ground points for corrosion, looseness or paint barriers; measure resistance to battery negative
Backprobe data lines and check for message activity with a scan tool; check for bus-off conditions

CAN bus (if used): recessive state ~2.5 V on CAN_H and CAN_L; dominant state ~3.5 V (CAN_H) and ~1.5 V (CAN_L) — verify differential toggling during communication
LIN bus (if used): idle ≈ battery voltage, frames pulled low for communication pulses
MOST (if used): optical/electrical link status should show activity — check transceiver status
Supply voltage to module: nominal battery voltage (12 V) with engine off; charging voltage (13.5–14.5 V) with engine running
Module ground: near 0.0 V with respect to battery negative (low resistance path)

Retrieve and record all U-codes and freeze-frame data. Note when the code sets and any related codes.
Clear codes, then operate the radio/disc functions to attempt to reproduce the fault while monitoring live data and network messages.
Inspect module connector and harness for corrosion, damage, water intrusion or mis-routed wiring. Repair or reseal as needed.
Verify proper supply and ground at the module: measure battery voltage at the module power pin and check ground resistance to chassis/battery negative.
Use a scan tool or CAN/LIN/MOST traffic monitor to observe messages from the disc player module. Confirm the module is present on the bus and check for malformed frames or bus errors.
If bus errors are present, isolate by disconnecting the disc player module (with ignition off) and observe whether bus errors or related DTCs clear. If the bus returns to normal with the module disconnected, suspect the module or its wiring.
Inspect/repair any wiring faults found. If wiring is intact, check for available software updates or reprogramming procedures for the disc player module and perform per manufacturer procedures.
If reprogramming does not resolve the issue, consider module replacement. After replacement, program/configure the new module and verify proper operation and that the DTC does not return.
If intermittent or vehicle-specific issues persist, consult technical service bulletins and wiring diagrams for proprietary bus details, or escalate to manufacturer-level diagnostics.

Intermittent connector pins (bent, corroded, or pushed out) at the disc player module
Data-line short to voltage or ground on the audio bus (CAN/LIN/MOST)
Module transmitting malformed frames due to internal firmware fault
Faulty vehicle ground or low supply voltage causing data corruption
Aftermarket device or incorrect replacement unit causing protocol mismatch