OBD Guide

U18CA

Lost Communication With Active Safety Control Module 1 On Flexray Bus

U18CA is an OBD-II diagnostic trouble code meaning: Lost Communication With Active Safety Control Module 1 On Flexray Bus. Common causes: broken or damaged flexray bus wires, short circuit in communication circuit. Estimated repair cost: $56–278.

Severity
🚨 Critical
Can you drive?
Do not drive — repair immediately
Approx. repair cost
$56–278 (est.)

Symptoms

  • Check Engine Light Is On
  • Active safety systems do not work (ABS, ESP, etc.)
  • Additional errors related to security systems appear
  • Possible problems starting the engine
  • The system may go into emergency mode

Causes

  • Broken or damaged Flexray bus wires
  • Short circuit in communication circuit
  • Active safety module malfunction
  • Module power problems
  • Corrosion or oxidation of contacts

How to Fix

  1. Check integrity of Flexray bus wiring
  2. Check the supply voltage of the active safety module
  3. Inspect all connectors for corrosion or damage.
  4. Conduct computer diagnostics to identify a specific malfunction
  5. Repair only from an authorized dealer

Related codes

FAQ

What does the U18CA code mean?

U18CA is an OBD-II diagnostic trouble code that indicates: Lost Communication With Active Safety Control Module 1 On Flexray Bus

What causes a U18CA error code?

The most common causes of U18CA include: Broken or damaged Flexray bus wires; Short circuit in communication circuit; Active safety module malfunction; Module power problems.

How do I fix a U18CA diagnostic trouble code?

To fix U18CA: Check integrity of Flexray bus wiring. Check the supply voltage of the active safety module. Inspect all connectors for corrosion or damage.. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with U18CA?

Do not drive — repair immediately

How much does it cost to fix U18CA?

The estimated repair cost for U18CA is $56–278. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat