OBD Guide
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U18AF

Lost Communications With Telematics Communications Interface Control Module On Ethernet Bus

U18AF is an OBD-II diagnostic trouble code meaning: Lost Communications With Telematics Communications Interface Control Module On Ethernet Bus. Common causes: open or short circuit in ethernet circuit, problems with power supply of the telematics module. Estimated repair cost: $56–278.

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

Symptoms

  • Lack of operation of remote services (for example, remote start)
  • Problems with the navigation system
  • Error message on the dashboard
  • Lack of emergency communication (e.g. eCall)
  • Inability to update vehicle software

Causes

  • Open or short circuit in Ethernet circuit
  • Problems with power supply of the telematics module
  • Malfunction of the telematics module itself
  • Connector problems or contact corrosion
  • Software failures in the module

How to Fix

  1. Check fuses associated with the telematics module
  2. Inspect connectors and wiring harness for damage
  3. Check the power and ground of the telematics module
  4. Perform Ethernet bus diagnostics using a scanner
  5. If necessary, replace the telematics module
  6. Update module software

Related codes

U18A0U18B0U18AE

FAQ

What does the U18AF code mean?

U18AF is an OBD-II diagnostic trouble code that indicates: Lost Communications With Telematics Communications Interface Control Module On Ethernet Bus

What causes a U18AF error code?

The most common causes of U18AF include: Open or short circuit in Ethernet circuit; Problems with power supply of the telematics module; Malfunction of the telematics module itself; Connector problems or contact corrosion.

How do I fix a U18AF diagnostic trouble code?

To fix U18AF: Check fuses associated with the telematics module. Inspect connectors and wiring harness for damage. Check the power and ground of the telematics module. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with U18AF?

Yes, but get it checked soon

How much does it cost to fix U18AF?

The estimated repair cost for U18AF is $56–278. Actual cost depends on your vehicle, location, and labor rates.

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See also: Russian version · NationStat