Powertrain, generic · Hybrid propulsion

P0AE4 Hybrid/EV Battery Precharge Contactor A Control Circuit/Open

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P0AE4 concerns the circuit that drives the coil of precharge contactor A, not its contacts. GM uses it in many hybrid and EV tables, with changing logic: the 2016 and 2019 OBDG02 tables look for an open high-side driver circuit, a control voltage between 1.15 and 2.81 V while commanded off, 40 of 50 samples at 12.5 ms, Type B, two trips. The 2019 OBDG01 version also catches a short to power while off and a coil current below 194 mA while on. The 2011 Volt table instead flags a short to battery voltage in the off state, Type A, one trip. With the coil not driven, precharge cannot start and the high-voltage system stays off. Low and high variants are P0AE6 and P0AE7.

Likely causes

Open control wire or loose connector at the contactor coil
Precharge contactor coil open internally
Control wire shorted to 12 V (GM 2011 and 2019 logic)
Driver stage in the battery or hybrid controller defective

Symptoms

  • Vehicle does not become ready to drive
  • MIL and hybrid or EV warning on
  • Charging not possible

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€100–2,500
Time1–5 h

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

Parts involved

hv battery precharge contactor awiring harnessbms

Related codes

P0AE5P0AE6P0AE7P0AE3P0AD9P0ADD

References: gsi.ext.gm.com, gsi.ext.gm.com, gsi.ext.gm.com.