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Engine-Codes – Generic – C1A72

C1A72 Code - Communication Error from FCM to Driving Support ECU

Quick Answer

The C1A72 diagnostic trouble code indicates a communication error between the Forward Camera Module (FCM) and the Driving Support Electronic Control Unit (ECU) in a vehicle. Common causes include Faulty wiring or connectors between the FCM and Driving Support ECU, Malfunctioning FCM or Driving Support ECU, Software glitches or updates causing communication errors. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means
C1A72 indicates Communication Error from FCM to Driving Support ECU.
Common causes
Common causes include Faulty wiring or connectors between the FCM and Driving Support ECU, Malfunctioning FCM or Driving Support ECU, Software glitches or updates causing communication errors.
Severity
High - diagnose this code as soon as possible.
Can I drive?
Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
What is this?
Table of contents Created and updated by William Orellana on Sep 10, 2024
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Code C1A72 Description

The C1A72 diagnostic trouble code indicates a communication error between the Forward Camera Module (FCM) and the Driving Support Electronic Control Unit (ECU) in a vehicle. This communication error can disrupt the flow of information between these two critical systems, affecting the vehicle's performance and safety features. The FCM is responsible for various driving support functions such as lane departure warning, automatic emergency braking, and adaptive cruise control. The Driving Support ECU processes the data from the FCM and coordinates the vehicle's response to potential hazards on the road.

OBDII Code C1A72 - Communication Error from FCM to Driving Support ECU
C1A72 Code - Communication Error from FCM to Driving Support ECU

Common Causes of C1A72

  1. Faulty wiring or connectors between the FCM and Driving Support ECU
  2. Malfunctioning FCM or Driving Support ECU
  3. Software glitches or updates causing communication errors
  4. Electrical interference or signal disruption
  5. Water damage or corrosion in the communication system components

Symptoms of C1A72

  1. Loss of lane departure warning functionality
  2. Inaccurate adaptive cruise control performance
  3. Dashboard warning lights related to driving support systems
  4. Vehicle entering limp mode

How to Fix C1A72

  1. Perform a comprehensive diagnostic scan to identify the exact cause of the communication error
  2. Inspect wiring, connectors, and components between the FCM and Driving Support ECU for any damage or corrosion
  3. Repair or replace any faulty wiring, connectors, or components
  4. Update software or perform reprogramming as necessary to resolve communication issues
  5. Conduct a thorough test drive to ensure the driving support systems are functioning properly after repairs

Cost to Fix C1A72

The cost of repairing a communication error between the FCM and Driving Support ECU can vary depending on the extent of the issue and the parts that need to be replaced. In general, this repair can range from $200 to $600, including parts and labor. However, specific diagnosis time and labor rates at auto repair shops can vary based on factors such as location, vehicle make and model, and engine type. It's recommended to check with local repair shops for a more accurate estimate.

What does this mean?

Tech Notes for C1A72

When replacing the Forward Recognition Camera, always replace it with a new one. If a Forward Recognition Camera which was installed in another vehicle is used, the information stored in the Forward Recognition Camera will not match the information from the vehicle. As a result, a DTC may be stored.

If the Forward Recognition Camera has been replaced with a new one, be sure to perform Forward Recognition Camera learning.

When replacing the Driving Support ECU Assembly, always replace it with a new one. If a Driving Support ECU Assembly which was installed in another vehicle is used, the information stored in the Driving Support ECU Assembly will not match the information from the vehicle. As a result, a DTC may be stored.

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Code C1A72 Information for Specific Makes

  • C1A72 Lexus — Communication Error from FCM to Driving Support ECU
  • C1A72 Toyota — Communication Error from FCM to Driving Support ECU
About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about C1A72 Code

What does the OBDII code C1A72 mean?

C1A72 indicates a communication error between the Forward Collision Mitigation (FCM) system and the Driving Support ECU, meaning data exchange between these components is disrupted.

What are common symptoms of the C1A72 code?

Symptoms may include illuminated warning lights (like the check engine or collision mitigation system light), deactivated driver assistance features, or erratic system behavior.

What causes the C1A72 code to trigger?

The code can be caused by faulty wiring, a damaged FCM module, a malfunctioning Driving Support ECU, or software issues in either module.

Can a weak battery cause the C1A72 code?

Yes, a weak or failing battery can lead to voltage irregularities, which may disrupt communication between the FCM and Driving Support ECU.

How is the C1A72 code diagnosed?

Technicians use a scan tool to verify the code, inspect wiring and connectors between the FCM and Driving Support ECU, and test the functionality of both modules.

Can I still drive with the C1A72 code active?

While the vehicle may still be drivable, driver assistance features like collision mitigation may not function, increasing the risk of an accident.

How can the C1A72 code be fixed?

Repairs may include checking and repairing wiring, replacing faulty connectors, updating module software, or replacing the FCM or Driving Support ECU if necessary.

Does the C1A72 code require reprogramming?

If the issue is due to outdated software, reprogramming or updating the affected modules may resolve the problem.

What tools are needed to fix the C1A72 code?

A diagnostic scan tool, a multimeter for electrical testing, and possibly manufacturer-specific tools for reprogramming or module replacement are required.

Is the C1A72 code covered under warranty?

It depends on the vehicle’s warranty terms and whether the issue is related to a defective part or wear and tear. Consult your warranty documentation or dealership for confirmation.

Discuss the causes and fixes for C1A72 OBDII Code

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