HomeTrouble CodesU0064

U0064 — Vehicle Communication Bus E

Generic OBD-II · all makesNetwork / communication

Code U0064 indicates a malfunction on 'Vehicle Communication Bus E,' which is one of the dedicated digital networks allowing the vehicle's various control modules to share data. When this code sets, it means one or more modules on this specific network are failing to transmit or receive messages properly, disrupting normal vehicle operations.

Symptoms

What causes it — most likely first

1. Wiring harness fault

An open circuit, short to ground, or short to power in the Bus E wiring is the most common cause, disrupting the digital signal between modules.

2. Failed module on Bus E

A module connected to this specific bus may have suffered an internal failure, preventing it from communicating or pulling the bus voltage down.

3. Corroded or loose connector

High resistance or a poor connection at a module or splice connector can disrupt the communication signal.

4. Power or ground issue

If a module on Bus E lacks proper power or ground, it cannot communicate, often triggering a bus code even though the bus wiring itself is intact.

5. Gateway or PCM failure

A failure of the main gateway or engine computer is possible but very rare; this is almost never the root cause of a U0064 code.

How it's diagnosed

  1. Perform a full vehicle module scan to identify which specific modules cannot communicate with the scan tool.
  2. Consult wiring diagrams to identify which modules are assigned to Bus E and locate the bus splice points.
  3. Inspect the wiring harness and connectors for Bus E for visible damage, chafing, corrosion, or loose pins.
  4. Measure bus voltage and resistance at the DLC or module connectors to check for shorts to ground/power or open circuits.
  5. Isolate modules on Bus E by disconnecting them one at a time to see if communication is restored, revealing the shorted module.

Code facts & related codes

SystemNetwork / communication
StandardizationSAE generic — identical on every make

Frequently asked

Is it safe to drive with a U0064 code?

Generally no. Since critical modules may not be communicating, vehicle behavior can be unpredictable, and safety systems like ABS or stability control may be disabled.

Does a U0064 code mean I need to replace the PCM (engine computer)?

Rarely. While a failed PCM can theoretically cause this, it is much more likely to be a wiring issue, a bad connector, or a failure of a specific sub-module on Bus E. Replacing the PCM is almost always a misdiagnosis.

Can a low battery cause this code?

Yes. Low system voltage can cause modules to drop off the communication network, triggering network codes. Always verify battery health and charging system output before diagnosing network faults.

What does 'Bus E' mean specifically?

Vehicles use multiple communication networks (buses) to organize data by speed and priority. Bus E refers to a specific sub-network, often dedicated to body controls, infotainment, or specific sensors, distinct from the primary high-speed engine bus.