Powertrain, generic · Hybrid propulsion

P0ACF Hybrid/EV Battery Pack Cooling Fan 3 Control Circuit/Open

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

Air-cooled traction batteries can use several blowers; P0ACF belongs to the third one and means the battery controller sees an open or otherwise invalid control line while it drives fan 3. CARB 1968.2 (e)(15.2.3)(B) requires the electrical inputs and outputs of the battery thermal management to be monitored like other comprehensive components. No manufacturer publicly documents this code; GM shows the method on fan 1 (P0A81): it checks the control voltage on the driver output and needs 16 failures before a Type B code is stored. Fan 1 and fan 2 have their own sets P0A81 and P0A96. Without the third blower the pack heats up faster, and power is limited.

Likely causes

Loose, corroded or unplugged connector at fan 3
Broken control wire between battery controller and fan 3
Fan motor or its built-in driver open internally
Fan output stage in the battery controller defective

Symptoms

  • Hybrid or EV system warning light, often with check engine light
  • Electric drive power reduced when the battery gets warm
  • No fan noise from the battery area when cooling is expected

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

P0AD0P0AD1P0AD2P0AD3P0A81P0A96

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