OBD Guide

C1A72

Communication Error from FCM to Driving Support ECU

C1A72 is an OBD-II diagnostic trouble code meaning: Communication Error from FCM to Driving Support ECU. Common causes: open or damaged wiring harness between fcm and driving support ecu, headlamp control module (fcm) malfunction. Estimated repair cost: $56–167.

Severity
⚠️ Medium
Can you drive?
Limited driving only, diagnose soon
Approx. repair cost
$56–167 (est.)

Symptoms

  • Incorrect operation of driver assistance systems
  • Error message on the dashboard
  • Disabling adaptive cruise control
  • Problems with automatic headlight switching

Causes

  • Open or damaged wiring harness between FCM and Driving Support ECU
  • Headlamp control module (FCM) malfunction
  • Problems with power supply to one of the modules
  • Malfunction of the driver assistance systems control unit
  • Problems with the CAN bus

How to Fix

  1. Check the integrity of the wiring harness between the FCM and Driving Support ECU
  2. Inspect connectors for oxidation or damage
  3. Check power and ground on both modules
  4. Scan other modules for related errors
  5. If necessary, replace the faulty module or restore the wiring harness

Related codes

FAQ

What does the C1A72 code mean?

C1A72 is an OBD-II diagnostic trouble code that indicates: Communication Error from FCM to Driving Support ECU

What causes a C1A72 error code?

The most common causes of C1A72 include: Open or damaged wiring harness between FCM and Driving Support ECU; Headlamp control module (FCM) malfunction; Problems with power supply to one of the modules; Malfunction of the driver assistance systems control unit.

How do I fix a C1A72 diagnostic trouble code?

To fix C1A72: Check the integrity of the wiring harness between the FCM and Driving Support ECU. Inspect connectors for oxidation or damage. Check power and ground on both modules. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with C1A72?

Limited driving only, diagnose soon

How much does it cost to fix C1A72?

The estimated repair cost for C1A72 is $56–167. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat