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Home / DTC / U0194 — Lost communication with the digital audio control module - B

U0194 — Lost communication with the digital audio control module - B

Detailed page for trouble code U0194.

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U0194

LAND ROVER U — Network/User

Lost communication with the digital audio control module - B

Brand: LAND ROVER
Type: U — Network/User
Views: UK: 4 EN: 8 RU: 4
AI status
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Completed 100%
Page language: EN

Causes

  • Digital audio control module (DACM) internal fault
  • Loss of module supply (battery/ignition feed) or ground
  • Open/short or corrosion in module connector or wiring harness
  • Damaged or shorted CAN bus/LIN wiring or poor termination
  • Blown fuse or relay feeding the audio module
  • Software/firmware mismatch or module configuration error

Symptoms

  • No audio or partial audio operation
  • Audio controls not responding or unavailable on infotainment screen
  • Related warning or message on instrument cluster (communication error)
  • Other modules showing linked network errors
  • Intermittent audio or loss of certain audio functions (phone, radio, navigation)

What to check

  • Read all stored and pending DTCs from all modules; note freeze frame and occurrence count
  • Verify vehicle battery voltage and perform a battery health check
  • Attempt to communicate directly with the digital audio control module via dealer-level scanner
  • Visually inspect module connector, wiring harness and grounds for corrosion, damage or loose pins
  • Check fuses and relays that supply the audio module
  • Measure module supply and ground voltages with ignition in the required state

Signal parameters

  • Module supply voltage: battery/ignition feed (approx. 11–14 V with engine off/on as appropriate)
  • Ground continuity to chassis ground (
  • CAN bus idle voltages: each line ~2.5 V (verify manufacturer spec); dominant state ~CAN_H ~3.5 V / CAN_L ~1.5 V
  • Differential CAN voltage when active (approx. 2.0 V differential when driven)
  • Resistance across CAN_H and CAN_L at key nodes (verify ~60 ohms across whole network)
  • Presence/periodicity of module-specific CAN IDs/messages using a serial data display or CAN sniffer

Diagnostic algorithm

  1. Record all codes and freeze frame data from all control modules.
  2. Verify battery condition and voltage. Low voltage can corrupt network communications.
  3. Visually inspect the digital audio control module connector and harness for corrosion, bent pins, water damage, or rodent/separation damage.
  4. Check fuses and relays for the audio module; replace any blown fuses and re-check communication.
  5. With a known-good scan tool, attempt to communicate with the DACM. Note if the module appears on the network list.
  6. Backprobe the module power and ground pins; verify ignition-switched and permanent supplies where applicable, and good ground continuity.
  7. Measure CAN_H and CAN_L at the module connector: confirm idle voltages and verify the lines respond (go dominant) when exercising a nearby module or using a CAN tester.
  8. If CAN lines are abnormal, trace wiring for opens/shorts to battery/ground or other modules; inspect splice points and junction boxes.
  9. Check for correct termination resistance across CAN_H and CAN_L (approx. 60 ohms across the network). Replace missing/incorrect terminators.
  10. If wiring and power/ground are good but the module does not respond, try to communicate with the module off-vehicle or use a known-good module if available to confirm module failure.
  11. If a replacement module is fitted, ensure proper programming/configuration and re-run network relearn procedures as required by manufacturer.
  12. Clear codes and road-test; monitor for reappearance and for any other network DTCs that might indicate the source module.

Likely causes

  • Corroded/loose connector at the audio module
  • Power or ground missing at the audio module
  • Failed audio module electronics
  • CAN bus wiring short to battery/ground or open circuit
  • Faulty or missing CAN bus termination resistor

Fault status

⚠️ Status
Lost communication with digital audio control module (DACM) - B. The module is not responding or its messages are missing from the vehicle data bus.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 0.5-2.0 hours

Similar codes

U0100 U0073 U0155 U0164 U0199
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