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U04A6 Invalid Data Received From Hybrid/EV Battery Interface Control Module F

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

U04A6 is set when interface control module F delivers messages the battery controller cannot accept. A board like this checks itself as well: in GM's 16OBDG02 table every interface module, F included, runs four processor performance tests once at each ignition change, for example confirming that its analogue-to-digital converter shows no stuck bits when the input is forced to its limits, Type A after 8 failures in 10 samples. Such internal faults get their own GM P1 codes; U04A6 is meant for the case where the receiver itself judges the incoming data unusable. No manufacturer documents U04A6 publicly. U01A5 means F has stopped talking, U033F that its software does not fit. Expect a hybrid or EV warning and restricted output.

Likely causes

Processor or converter fault on interface board F
Contact fault on the internal data link to module F
Supply dropouts of the battery electronics during switch-on

Symptoms

  • Hybrid or EV warning, MIL on plug-in hybrids
  • Reduced power output

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€150–2,800
Time1.5–8 h

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

Parts involved

hv battery interface module f

Related codes

U01A5U033FU04A5U04A7

References: gsi.ext.gm.com, law.cornell.edu.