Powertrain, generic (extended)

P2C8A Hybrid/EV Battery Interface Control Module A Performance

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

Battery interface control modules are the satellite boards in the traction battery that measure cell voltages and temperatures and report them to the battery energy control module. P2C8A says module A is reachable but not working properly. GM uses the code on its Ultium EVs: preliminary information PIP6021 (Lyriq, Blazer EV, Equinox EV, later Optiq and Vistiq) blames a BECM calibration anomaly when P2C8A, P2C8B and U3577-U35AF are all set, with MIL or Service High Voltage and a draining 12 V battery; the fix is BECM programming and two manual resets. PIP6081 calls the same pattern a cell monitoring unit brownout on Hummer EV, Silverado EV and Escalade IQ. The earlier Volt checked comparable modules with its own code, a key value test, Type B.

Likely causes

Battery energy control module software or calibration error
Supply dip at the cell monitoring module (12 V battery weak, wake-up issue)
Damaged communication or supply harness inside the battery pack
Failed interface module A board

Symptoms

  • MIL or Service High Voltage message
  • 12 V battery discharging while parked
  • Many battery communication codes stored at the same time

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€100–5,000
Time1.5–8 h

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

Parts involved

hybrid battery interface cm abms

Related codes

P2C8BU01A0U033AU04A1

References: static.nhtsa.gov, static.nhtsa.gov, gsi.ext.gm.com.