What Does P0ACF Mean?
The control circuit for hybrid battery pack cooling fan 3 has an open circuit or general electrical fault. This fan is one of multiple fans responsible for maintaining safe battery pack temperatures during charging and driving. Without this fan operating, the affected battery zone may overheat under load, triggering power derating or a battery protection shutdown.
Safety Warning
Loss of a battery cooling fan reduces the system's ability to dissipate heat during high-demand driving or fast charging. This can lead to thermal runaway in extreme cases. The vehicle will likely limit power and charging rates to compensate, but immediate repair is strongly recommended.
Common Causes
28%
Open circuit in the cooling fan 3 control wiring
25%
Failed cooling fan 3 motor (burned out or seized)
20%
Blown fuse or fusible link for the fan 3 circuit
15%
Corroded or disconnected fan connector
12%
Battery management system driver circuit failure
Diagnostic Steps
1
Check the fuse and relay for the battery cooling fan 3 circuit; replace if blown and test for underlying short that caused the failure.
2
Locate the cooling fan 3 connector and inspect for corrosion, disconnection, or heat damage to the terminals.
3
Measure voltage at the fan connector with the BMS commanding the fan on; no voltage indicates a wiring or BMS driver issue.
4
Apply direct battery voltage to the fan motor terminals (with appropriate fuse protection) to confirm the motor spins freely and is not seized.
5
Measure continuity of the control circuit wiring from the BMS module to the fan connector; repair any open segments found.
6
If wiring and fan test good, the BMS driver transistor or relay driver circuit may be at fault; check for TSBs or replace the module.
Estimated Repair Cost
$200 - $800
Parts + labor, varies by vehicle and location
The control circuit for hybrid battery pack cooling fan 3 has an open circuit or general electrical fault. This fan is one of multiple fans responsible for maintaining safe battery pack temperatures during charging and driving. Without this fan operating, the affected battery zone may overheat under...
The most common cause of P0ACF (Hybrid Battery Pack Cooling Fan 3 Control Circuit/Open) is: Open circuit in the cooling fan 3 control wiring
Typical repair costs for P0ACF range from $200 to $800, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Loss of a battery cooling fan reduces the system's ability to dissipate heat during high-demand driving or fast charging. This can lead to thermal runaway in extreme cases. The vehicle will likely limit power and charging rates to compensate, but immediate repair is strongly recommended.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0ACF to identify the root cause.
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Quick Info
Category
Powertrain
System
Hybrid Battery Cooling System
Difficulty
Type
Generic (SAE)
Recommended Tools
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