Powertrain, generic · Hybrid propulsion

P0A8F 14 Volt Power Module System Performance

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

P0A8F means the 14 V power module (DC/DC converter for the 12 V network) does not perform as expected even though its signals are electrically in range. GM's 2013 eAssist tables use it as a correlation test: with the APM commanded on and ignition voltage 9 to 32 V, the APM's own low-voltage reading and the run/crank voltage measured by the controller must agree within 4.5 V. A larger difference over 3.75 s in a 5 s window sets the code as Type B, two trips to MIL. A high resistance in the 12 V output path or ground, a drifting sensor or a converter that cannot hold its target can all cause this. P0A8D and P0A8E cover sensor circuit low/high faults.

Likely causes

High resistance in 12 V output cable, fuse link or ground
Drifting voltage sensor in the module
Converter unable to hold its target voltage

Symptoms

  • MIL and charging/hybrid warning
  • Low or fluctuating 12 V voltage

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€80–1,800
Time1–4 h

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

Parts involved

pm14v moduledcdc converter

Related codes

P0A8BP0A8CP0A8DP0A8E

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