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

What it means

The HV battery pack cooling fan 3 reports a control circuit/open condition. Battery thermal management is impaired.

At a glance

• Usually lights the check-engine light
• The engine or gearbox may go into limp mode

How it works

Battery cooling fan 3 is one of the fans that moves air through the hybrid or EV battery pack to control temperature. The control system monitors its electrical control path, and this code sets when fan 3's circuit is open and the fan cannot be reliably commanded.

Common causes

Most likely first.

1. Open in fan control wire
2. Open fan motor
3. Pin pushed back out of connector body

Symptoms

• EV/hybrid system warning light on
• Reduced power output or limp mode
• Charging may fail or be slowed
• Reduced electric range

How to diagnose it

1. Record freeze-frame data and check fan command and battery temperature data to establish when fan 3 was expected to operate.
2. Inspect the fan 3 connector and accessible wiring for a disconnected plug, damage, or a pushed-back terminal.
3. Check the fan 3 control circuit for continuity and connector contact using the wiring diagram and manufacturer's procedure.
4. Test fan 3's motor and control path as specified by the manufacturer.
5. If the circuit and motor pass, check the fan control module or battery control module for related faults.

Common fixes

• Reconnect the fan 3 plug and correctly seat any pushed-back terminal.
• Repair an open or damaged fan 3 control wire.
• Replace fan 3 if its motor circuit is open.
• Repair or replace a confirmed faulty fan control component.

Can I keep driving?

Avoid fast charging, heavy loads, and long demanding drives because the battery pack may not receive enough cooling and the vehicle may reduce power. Arrange prompt repair, and stop safely if a temperature warning or pronounced power reduction occurs.