Network, generic

U064A Lost Communication With Hybrid/EV Battery Pack Current Sensor A

Check engine lightOn

EmissionsRelevant

Drive cycleNot required

Limp modePossible

Battery management needs the pack current to count charge in and out and to judge state of charge and state of health. Many packs measure it with a self-contained sensor that sends its value over CAN; LEM's CAB series, for example, transmits on high-speed CAN at 500 kbit/s and is built for ASIL C. U064A records that current sensor A has stopped sending, while an analog sensor would report wiring faults via P0ABF to P0AC3. No manufacturer documents U064A publicly. CARB 1968.2 (e)(15.2.3)(A)(iv) requires the electronic inputs of the energy storage system to be monitored, which on hybrids points to a lit MIL. Without a current value the battery controller cannot track charge and normally restricts charging and discharging sharply.

Likely causes

CAN, supply or ground wiring of sensor A inside or at the pack damaged

Current sensor A failed

Moisture or corrosion at the pack's low-voltage connector

Battery energy control module fault or software

Symptoms

Hybrid or EV battery warning, on hybrids also the MIL
Strongly reduced drive power or charging refused
Implausible state-of-charge display

Repair estimate

DifficultyShop_onlyWorkshop job

Parts and labour€150–2,000

Time1–5 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

hv battery current sensor avehicle bus wiring

References: law.cornell.edu, lem.com.