P0AA4 Fault Code

Hybrid Battery Negative Contactor Circuit Stuck Closed

• What does that mean?
• Symptoms
• Causes
• Solutions

The P0AA4 fault code indicates that the hybrid battery negative contactor circuit is stuck closed. This condition can prevent the hybrid system from properly isolating the battery when it is not in use, potentially leading to battery drain or safety concerns. It's vital to address this issue promptly to ensure the efficient operation of the hybrid vehicle.

What are the symptoms of the P0AA4 code?

Common symptoms associated with the P0AA4 fault code include:

• The hybrid vehicle may not start or operate as intended
• Warning lights illuminated on the dashboard, particularly the check engine light
• Reduced performance or efficiency of the hybrid system
• Unusual clicking or electrical noises from the battery area

What causes the P0AA4 code?

This fault may be caused by various factors including:

• A malfunctioning negative contactor
• Faulty wiring or connections in the contactor circuit
• Issues with the Battery Energy Control Module (BECM)
• Short circuits or electrical interference in the circuit

How to fix P0AA4?

To fix the P0AA4 fault code, consider the following steps:

• Inspect and test the negative contactor for proper operation and replace it if faulty.
• Check wiring and connectors for damage or corrosion and repair as needed.
• Diagnose the Battery Energy Control Module and ensure it functions correctly.
• If necessary, use a diagnostic scanner to clear the fault codes after repairs and test drive the vehicle to confirm the issue is resolved.