Network, generic

U014A Lost Communication With Battery Energy Control Module C

Check engine lightOn
EmissionsNot relevant
Drive cycleNot required
Limp modePossible

U014A concerns a third battery energy control module, C. Hybrid and electric vehicles use such units to watch cell voltages, temperatures and state of charge and to protect the pack; distributed or modular designs give several sub-packs their own controller, which is where letters beyond A and B come in. No manufacturer documents U014A publicly. The best documented relative is U0111 for module A: in GM's 2018 hybrid tables the hybrid powertrain controller flags missing BECM messages after 500 ms, once bus communication has run for at least 5 s and the battery holds 10.2 V or more, and rates it Type B with MIL after two trips. Without data from C the system cannot judge that part of the pack, so expect reduced power, blocked charging or no ready mode. U0111, U0112 and U014C cover modules A, B and D, U044B invalid data from C.

Likely causes

Low-voltage supply, fuse or ground of battery module C missing
Bus wiring or connector inside or at the battery pack damaged or corroded
Moisture or coolant in the pack affecting module C
Battery module C internally faulty or not programmed

Symptoms

  • Hybrid or EV system warning, reduced power
  • Charging refused or stopped
  • Vehicle may not enter ready mode

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€100–3,000
Time1–6 h

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

Parts involved

battery energy module ccan bus

Related codes

U0111U0112U014CU044B

References: gsi.ext.gm.com, en.wikipedia.org, law.cornell.edu.