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

What it means

The HV battery pack cooling fan 3 reports a control circuit high 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 controlled through an electrical circuit that lets the hybrid or EV battery system request airflow. This code sets when the fan 3 control circuit signal is above its expected range, which can result from a short to battery voltage, an open motor circuit, or a connection fault.

Common causes

Most likely first.

1. Wire shorted to B+
2. Open motor
3. Connector pins corroded - high contact resistance

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 3 command, battery temperature, and related cooling codes.
2. Inspect the fan 3 connector and harness for an open connection, corrosion, damaged pins, or wiring shorted toward battery voltage.
3. Use the wiring diagram to test the control circuit for a short to battery voltage and check continuity through the motor circuit.
4. Test fan 3 and its control circuit using the manufacturer's procedure and specification.
5. If the fan and harness pass, check the fan control module or battery control module for an output fault.

Common fixes

• Reconnect or repair an open fan 3 connector or wire.
• Repair wiring shorted to battery voltage.
• Replace fan 3 if its motor circuit is open or fails testing.
• Repair or replace a confirmed faulty fan control component.

Can I keep driving?

Avoid fast charging, heavy loads, and long demanding drives because the vehicle may not be able to control battery cooling correctly. Stop safely if the battery temperature warning appears or power is significantly reduced, and arrange prompt diagnosis.