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DTC codes / U06xx · Network communication / U064C

U064CLost Communication With Hybrid/EV Battery Pack Current Sensor C

U064C is a network communication code indicating that one or more control modules have lost the CAN (Controller Area Network) signal from the hybrid or electric vehicle battery pack current sensor designated as Sensor C. The computer detected that expected periodic messages from this sensor stopped arriving over the communication bus, which can disable battery monitoring strategies and set related faults.

SystemNetwork
Code typeGeneric (all makes)
SeverityMedium
Fix difficultyProfessional
AreaNetwork communication

Symptoms you may notice

  • Illumination of the check engine light, hybrid system warning, or service vehicle soon message
  • Often no symptoms besides the warning light, with the vehicle driving normally
  • Reduced hybrid or electric propulsion power, entering limp mode, or refusal to start
  • Inaccurate or frozen state-of-charge and battery current readings on the dash or scan tool
  • Automatic disabling of regenerative braking or stop-start functionality
  • Multiple unrelated warning lights due to shared bus communication loss

Common causes, most likely first

  1. Damaged, corroded, or disconnected wiring or connector at the current sensor C or its in-line harness
  2. Failed hybrid/EV battery pack current sensor C itself
  3. Blown fuse or poor power/ground supply to the sensor or its control module
  4. CAN bus wiring fault such as an open, short to ground, or short to voltage on the network segment
  5. Failed or intermittently failing control module that publishes the sensor C data
  6. Water intrusion or physical damage to the battery pack harness or sensor mounting area
  7. Software or calibration issue in a module after battery service or replacement

How to diagnose and fix it

  1. Connect a scan tool and record all stored codes in every module, then verify U064C is current and not history
  2. Inspect the current sensor C connector and harness for corrosion, loose pins, chafing, or water intrusion
  3. Check the sensor circuit for proper reference voltage, ground, and continuity using a multimeter and wiring diagram
  4. Perform a CAN bus integrity test by measuring resistance and voltage on the network at the diagnostic connector
  5. Substitute a known-good current sensor C or perform a bidirectional test if the scan tool supports it
  6. Clear codes and perform a road test with live data monitoring of battery current sensor C to confirm the repair
  7. If the fault persists, diagnose the publishing control module and check for applicable software updates

Why current sensor C communication fails

  • A loose 12-volt battery terminal or poor chassis ground can corrupt CAN bus messages and set U064C even when the hybrid battery sensor is fine.
  • Technicians often replace the current sensor C when the real fault is a chafed harness behind the battery pack, so always flex-test the wiring while watching live data.
  • U064C can be stored alongside U064A and U064B when multiple current sensors share a common power or ground circuit, pointing to a supply fault rather than three separate sensor failures.
  • After a hybrid battery service, a missing or incorrect calibration value can cause the module to stop publishing sensor C data and set this code without any physical wiring problem.
  • Some vehicles set U064C only after several consecutive drive cycles with no sensor C message, so a single intermittent glitch may clear itself and mislead diagnosis.

Can I keep driving with U064C?

You can usually drive the vehicle if it runs normally and only the warning light is on, but avoid heavy acceleration, towing, or long trips until the fault is diagnosed. If the vehicle enters limp mode, refuses to start, or shows a hybrid battery warning, stop driving and arrange professional service.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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