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U04A7 Invalid Data Received From Hybrid/EV Battery Interface Control Module G

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

U04A7 points to interface module G. In a modular battery management system each board sits at a different potential: the ground of the top module can be hundreds of volts above that of the bottom one, so the boards talk through isolated links such as optocouplers or radio. Interference, moisture in a connector or an ageing isolator can corrupt the frames of a single board without breaking the link altogether, and the battery controller then logs an invalid-data code for that letter. No manufacturer publishes U04A7 or thresholds for it. In GM's table 16OBDG02, G is the seventh of eight boards. U01A6 stands for lost contact with G, U0340 for a software mismatch. Charging or drive power may be limited.

Likely causes

Moisture or corrosion at internal connectors (leaking pack seal)
Failing isolated communication stage on board G
Interface control module G otherwise defective

Symptoms

  • Battery or hybrid system warning
  • Charging or drive power limited
  • Fault may come and go with humidity or temperature

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€150–3,500
Time2–10 h

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

Parts involved

hv battery interface module g

Related codes

U01A6U0340U04A6U04A8

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