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U1064 – What Does It Mean and How To Fix It

This is one of the most frequent OBD2 trouble codes. Read the full article below to know what it means, how to fix it, and what other codes may show related to it.

Definition

U1064 is an OBD-II Code that refers to Lost Communication with Body Control Module

Meaning

A U1064 code is a manufacturer specific GMC/Chevrolet diagnostic trouble code that occurs when the other control modules on the vehicle are not communicating with each other. In this instance the Controller Area Network bus communications, or simply CAN indicates there’s a loss of communication with the body control module. The body control module is responsible for things like the door locks, power windows, and other interior accessories.

Causes

Common causes for this code include:

  • Malfunctioning Body Control Module (BCM) 
  • BCM harness is open or shorted
  • BCM circuit poor electrical connection

Symptoms

The symptoms of a U1064 code are:

  • Illuminated Check Engine Light
  • Power windows, door locks, and other accessories may not work 
  • Communication error message on the driver information center

Diagnosis

To diagnose a U1064 DTC code, a technician would:

  1. Scan for codes in the ECM and look at the freeze frame data for failure.
  2. Visually inspect the BCM harness for damage.
  3. Check the voltage of the battery and clean all the battery terminals and ground points.
  4. Verify that there is no loose, damaged, or corroded wiring anywhere in the BCM circuit.
  5. Connect a scan tool to the vehicle and check for any other codes that may be stored in the ECM.

Common mistakes

The following are some of the most common mistakes that a technician may make when diagnosing a U1064 code:

  • Not thoroughly inspecting all the wiring and connectors.
  • Not checking the fuses.
  • Not properly testing the BCM circuit.
  • Reinstalling the BCM without properly testing it.

How serious is this?

A U1064 code in most cases is a more serious issue and in rare cases, where the BCM is found to be bad, other modules on the vehicle may not be able to communicate with each other which could lead to further damage.

What repairs can fix the code?

repair manuals

The following are solutions that may fix this problem:

  • Repair or replace any faulty parts such as wiring, connectors, or control modules
  • Check all the grounds on the vehicle
  • Resolve any communication issues between modules
  • Replace the Body Control Module
  • By carefully reading the factory service manuals

Related codes

A U1064 is related to and may be accompanied by the following codes:

U0073- Lost Communication with Control Module on Bus

U0100- Lost Communication with Engine Control Module

U0102- Lost Communication with Transmission Control Module

U0103- Lost Communication with Brake Control Module

U0104- Lost Communication with Steering Control Module

Conclusion

In conclusion, the U1064 code is a diagnostic trouble code that refers to a problem with the communication between the other control modules on the vehicle. The most common causes for this code include a malfunctioning body control module, a short or open in the BCM harness, or a poor electrical connection in the BCM circuit. The symptoms of this code include an illuminated check engine light, power windows and door locks that may not work, and communication error messages on the driver information center. To properly diagnose this code, it is important to inspect all wiring and connectors, check for fuses, test the BCM circuit, and connect a scan tool to look for any other codes that may be stored in the ECM. In some cases, the Body Control Module may need to be replaced.