U0237

Code

LAND ROVER U — Network/User

Lost communication with the digital audio control module - C

Brand: LAND ROVER

Type: U — Network/User

Views: UK: 17 EN: 24 RU: 19

AI status

Completed

ready

Completed 100%

Page language: EN

Causes

Open or short in CAN bus wiring (CAN_H or CAN_L) to battery or ground
Damaged or corroded connector at the digital audio control module
Module has lost power or ground (fuse, wiring, poor ground)
Failed digital audio control module
Incorrect or missing module programming/software
Faulty termination resistor or missing CAN terminator

Symptoms

No audio, radio, or media functions from the affected head unit
Error messages or warnings on the instrument cluster or infotainment screen
Other modules reporting related U-codes or network errors
Intermittent or no response from steering wheel audio controls
Loss of features that rely on the audio module (Bluetooth, navigation audio, phone)

What to check

Read all stored and pending DTCs and note related U-codes
Verify module presence with a diagnostic tool (module listed/responding)
Check vehicle battery voltage and key-on voltage supply to module
Inspect fuses and fusible links related to the audio/control module
Visually inspect connectors and wiring for corrosion, damage, or loose pins at the module and junctions
Measure CAN bus voltages at the module connector with ignition ON (engine off)

Signal parameters

CAN bus recessive idle voltages: CAN_H ≈ 2.5 V, CAN_L ≈ 2.5 V
CAN bus dominant voltages: CAN_H ≈ 3.5 V, CAN_L ≈ 1.5 V (approximate differential ≈ 2.0 V)
Expected bus termination: ~60 ohms measured across CAN_H to CAN_L (two 120 Ω terminators in parallel)
Common CAN bus data rates: 125 kbps, 250 kbps, or 500 kbps (verify vehicle-specific rate)
No repetitive dominant state (bus should show alternating traffic when modules communicate)

Diagnostic algorithm

Use a diagnostic scan tool to confirm U0237 and list other U-codes; note freeze frame and active/inactive status.
Verify the digital audio control module is present in the tool’s module list. If not present, attempt to communicate again with key cycled.
Check battery voltage and inspect/verify power and ground circuits to the audio module (fuses, pins, ground connections). Repair as required.
Visually inspect the module connector(s) and wiring harness for corrosion, bent pins, water ingress, or damage; repair wiring or connector faults.
With ignition ON (engine off), measure CAN_H and CAN_L at the module connector: confirm idle voltages (~2.5 V) and a healthy differential when traffic is present. Compare to known-good location if available.
Measure resistance across CAN_H to CAN_L with key OFF; expected ≈60 ohms. If open or incorrect, trace wiring to find open/short or missing terminator.
Check for shorts to battery or ground on each CAN line (backprobe and reference to chassis and battery). Repair any shorts.
Disconnect the audio module and see if network communication is restored or if other modules report restored communication (isolate to determine if module is loading the bus).
Perform a wiggle test on harnesses/connectors while monitoring bus for changes or intermittent communication to find intermittent faults.
Check for recent module replacements or aftermarket installations; remove or reprogram suspect devices.
If wiring and power/grounds check OK and bus signals are valid but module doesn’t respond, consider module failure and follow manufacturer procedures for reprogramming or replacement. Clear codes and retest.
Consult Land Rover technical service bulletins for vehicle-specific guidance and follow the factory wiring diagrams during repair.

Likely causes

Corroded or loose connector at the audio module
Blown fuse or disconnected power/ground to the audio module
Open/short on CAN_H or CAN_L near the module harness
Failed audio control module or internal CAN transceiver
Missing/incorrect software calibration after module replacement

Fault status

⚠️ Status

Lost communication with the digital audio control module - C

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0-4.0 hours

Repair manuals

Manual library for LAND ROVER

320

Browse 320 LAND ROVER manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.

LAND ROVER

Your experience will help others

+100 karma for a short comment :)

Was this AI description helpful?

Your feedback helps improve AI descriptions.

👍 Like 0 👎 Dislike 0

Send to email

U0237 — Lost communication with the digital audio control module - C