Powertrain, generic · Hybrid propulsion

P0AE5 Hybrid/EV Battery Precharge Contactor A Control Circuit Range/Performance

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P0AE5 reports that the precharge function works electrically but does not deliver the expected result, so the controller judges the circuit implausible. Ford documents it in special service message SSM 47129: 2013-18 C-MAX and Fusion Hybrid and Energi models and the MKZ Hybrid may not start, with P0AE5 stored in the battery energy control module. When pinpoint tests show that the DC/DC converter, the cabin coolant heater or the A/C compressor has a low internal resistance on its high-voltage side, Ford replaces only that component, not the battery junction box. A load that drags the bus down keeps the precharge from reaching its target. Open, low and high driver faults are P0AE4, P0AE6 and P0AE7.

Likely causes

High-voltage consumer with low internal resistance (DC/DC converter, coolant heater, A/C compressor)
Precharge resistor degraded or wrong value
Precharge contactor responding slowly or with high contact resistance

Symptoms

  • Vehicle does not start or become ready
  • Red warning triangle or hybrid warning in the cluster
  • Possible additional codes from the faulty high-voltage consumer

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€300–2,500
Time1.5–6 h

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

Parts involved

hv battery precharge contactor awiring harnessbms

Related codes

P0AE4P0AE6P0AE7P0C78P0AE3

References: static.nhtsa.gov, law.cornell.edu.