Powertrain, generic · Hybrid propulsion

P0AD3 Hybrid/EV Battery Pack Cooling Fan 3 Control Circuit High

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

With P0AD3 the battery controller finds the control line of cooling fan 3 at a voltage that is too high for the commanded state, pointing to a short to a supply voltage or a fan input that no longer pulls the line down. No manufacturer publicly documents this code; GM's analogous fan 1 code P0A85 trips when the control voltage exceeds 9 V while the fan is driven, Type B. Siblings: P0AD2 for the low side, P0ACF for an open line, P0AD1 if the fan keeps running. CARB 1968.2 calls for this circuit monitoring on battery thermal management parts. Depending on the fault the fan runs permanently or not at all, and the pack may be derated.

Likely causes

Control wire shorted to 12 V or another supply
Fan electronics no longer loading the control line
Bent or bridged pins in the fan connector
Battery controller output stage defective

Symptoms

  • Hybrid or EV system warning light
  • Fan 3 runs constantly or not at all
  • Reduced electric power when the battery is warm

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€80–600
Time0.5–3 h

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

Parts involved

hv battery cooling fan 3wiring harnessbms

Related codes

P0ACFP0AD2P0AD1P0A85P0A9A

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