P0AA5 Fault Code

Hybrid Battery Negative Contactor Circuit Stuck Open

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

The P0AA5 fault code refers to an issue with the hybrid battery negative contactor circuit being stuck open. This can prevent the hybrid battery from being properly connected to the vehicle's electrical system, which can lead to reduced performance or a complete failure to start. It’s essential to address this code promptly to maintain the vehicle's hybrid system functionality.

What are the symptoms of the P0AA5 code?

Drivers may experience various symptoms when this code appears, such as:

• Warning lights on the dashboard, typically the check engine or hybrid system warning lights
• Reduced power or the vehicle may not start
• Unresponsive electric drive system
• Possible difficulty in switching gears in hybrid vehicles

What causes the P0AA5 code?

Common causes for the P0AA5 fault code include:

• Faulty hybrid relay or contactor
• Broken or damaged wiring in the battery circuit
• Corrosion at connection points
• Issues with the vehicle’s battery management system
• High resistance or open circuits due to wear and tear

How to fix P0AA5?

To resolve the P0AA5 fault, you can take the following actions:

• Inspect and replace the faulty hybrid relay or contactor if necessary
• Check and repair any damaged wiring or connectors in the hybrid battery circuit
• Clean corrosion from all electrical connection points to ensure good conductivity
• Use a diagnostic tool to reset the fault code and verify that the issue is resolved
• In some cases, reprogramming or updating the battery management software may be required