Powertrain, generic · Hybrid propulsion

P0A87 14 Volt Power Module Current Sensor A Circuit Range/Performance

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

This code means the current sensor of the 14 V power module (DC/DC converter, GM: APM) delivers values that are electrically valid but implausible. GM's 2016 eAssist tables (hybrid control processor HPC1) describe a stuck-in-range test: once per key cycle, while the high-voltage contactors are open and then move to precharge, the converter should be off, so the averaged input current must be near zero. If the average is 0.50 A or more, P0A87 sets as a Type B code, so the MIL comes on after two failed trips. The test is skipped while P0A88 or P0A89 is active. Unlike those circuit low/high codes, the wiring is usually intact here; a sensor with offset drift is the typical finding.

Likely causes

Current sensor zero-point drift inside the power module
Converter actually conducting current when it should be off (internal module fault)
Ground or reference fault distorting the sensor signal

Symptoms

  • MIL on after two drive cycles
  • Usually no driveability change
  • Possible reduced 12 V charging if the converter is limited

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€100–1,800
Time1–4 h

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

Parts involved

pm14v current sensor awiring harnessdcdc converter

Related codes

P0A86P0A88P0A89P0A8AP0CC5

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