Powertrain, generic · Hybrid propulsion

P0A8D 14 Volt Power Module System Voltage Low

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

P0A8D reports too low a voltage at the 14 V power module (DC/DC converter feeding the 12 V network). GM uses it in its 2013 eAssist tables as the circuit-low check of the APM low-voltage sensor: if that sensor reads below 1 V for 1.5 s within a 2 s window while ignition voltage is 9 to 32 V, the code sets; it passes again above 1.5 V. It is Type B, two trips to MIL. Because a real 12 V network cannot be at 1 V with the ignition on, GM's version really points to an open or shorted voltage sense line or a failed sensor, not a flat battery. Other makers may apply the code to genuine undervoltage. P0A8E is the high counterpart, P0A8F the correlation check.

Likely causes

Voltage sense line open or shorted to ground
Voltage sensor inside the power module failed
Converter not delivering output (fuse, output cable)

Symptoms

  • MIL and charging/hybrid warning
  • 12 V battery discharges
  • Start/stop disabled

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

P0A8BP0A8CP0A8EP0A8FP0562

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