OBD Guide
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U18B4

Lost Communication With Radio On Ethernet Bus

U18B4 is an OBD-II diagnostic trouble code meaning: Lost Communication With Radio On Ethernet Bus. Common causes: broken or damaged ethernet cable, audio system (radio) malfunction. Estimated repair cost: $56–278.

Severity
⚠️ Medium
Can you drive?
Yes, but get it checked soon
Approx. repair cost
$56–278 (est.)

Symptoms

  • Audio system doesn't work
  • No sound in the cabin
  • Problems with the multimedia system
  • Error message on display
  • Reset radio settings

Causes

  • Broken or damaged Ethernet cable
  • Audio system (radio) malfunction
  • Problems with the control unit
  • Short circuit in the circuit
  • Software glitch

How to Fix

  1. Check the integrity of the Ethernet cable
  2. Diagnose the operation of the audio system
  3. Check connector connections
  4. Update system software
  5. Replace faulty components

Related codes

U18B3U18B5U18B6

FAQ

What does the U18B4 code mean?

U18B4 is an OBD-II diagnostic trouble code that indicates: Lost Communication With Radio On Ethernet Bus

What causes a U18B4 error code?

The most common causes of U18B4 include: Broken or damaged Ethernet cable; Audio system (radio) malfunction; Problems with the control unit; Short circuit in the circuit.

How do I fix a U18B4 diagnostic trouble code?

To fix U18B4: Check the integrity of the Ethernet cable. Diagnose the operation of the audio system. Check connector connections. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with U18B4?

Yes, but get it checked soon

How much does it cost to fix U18B4?

The estimated repair cost for U18B4 is $56–278. Actual cost depends on your vehicle, location, and labor rates.

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See also: Russian version · NationStat