AutoCodes – Chevrolet – P0AA4 Chevrolet

P0AA4 Chevrolet Code - Hybrid/EV Battery Negative Contactor Circuit Stuck Closed

Quick Answer

The hybrid/EV battery contains 4 high voltage contactors and 1 solid state relay (transistor). Common causes include Faulty Battery Energy Control Module, Battery Energy Control Module harness is open or shorted, Battery Energy Control Module circuit poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: P0AA4 Chevrolet indicates Hybrid/EV Battery Negative Contactor Circuit Stuck Closed.
Common causes: Common causes include Faulty Battery Energy Control Module, Battery Energy Control Module harness is open or shorted, Battery Energy Control Module circuit poor electrical connection.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

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Code Popularity 1,562

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Apr 27, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P0AA4 Chevrolet Description

The hybrid/EV battery contains 4 high voltage contactors and 1 solid state relay (transistor). The high voltage contactors and transistor allow the high voltage DC batteries to be connected to the vehicle or contain the high voltage DC within the hybrid/EV battery assembly. The 4 high voltage contactors consist of a main positive high voltage contactor, main negative high voltage contactor, charge positive high voltage contactor and a precharge negative high voltage contactor. The transistor controls the battery heater high voltage positive circuit. The contactors and transistor close and open in a specific sequence controlled by the hybrid/EV powertrain control module 2. The hybrid/EV powertrain control module 2 supplies voltage to the control circuit for each high voltage contactor/transistor. Ground is provided through a vehicle ground external of the high voltage battery.

OBDII Code P0AA4 Chevrolet - Hybrid/EV Battery Negative Contactor Circuit Stuck Closed - AutoCodes.com — P0AA4 Chevrolet Code - Hybrid/EV Battery Negative Contactor Circuit Stuck Closed

What does this mean?

What are the Possible Causes of the DTC P0AA4 Chevrolet?

Faulty Battery Energy Control Module
Battery Energy Control Module harness is open or shorted
Battery Energy Control Module circuit poor electrical connection

How to Fix the DTC P0AA4 Chevrolet?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0AA4 Chevrolet code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about P0AA4 Chevrolet Code

1. What does the OBDII code P0AA4 mean for a Chevrolet vehicle?

P0AA4 indicates that the Hybrid/EV Battery Negative Contactor Circuit is stuck closed, meaning the system has detected an issue where the high-voltage battery's negative contactor is not functioning properly.

2. What are the common symptoms of the P0AA4 code in a Chevrolet?

Symptoms may include the Check Engine Light or Hybrid/EV system warning light turning on, reduced vehicle performance, limited high-voltage system functionality, or the vehicle failing to start.

3. What causes the P0AA4 code to appear in a Chevrolet?

Common causes include a malfunctioning high-voltage battery contactor, damaged wiring in the contactor circuit, a failed relay, or issues with the hybrid/EV battery control module.

4. Can I drive my Chevrolet with the P0AA4 code?

It is not recommended to drive the vehicle with this code active, as it may indicate a critical issue with the high-voltage battery system, potentially leading to safety concerns or further damage.

5. How is the P0AA4 code diagnosed in a Chevrolet?

A technician will use a scan tool to confirm the code, inspect the high-voltage battery contactor circuit and wiring for damage, test the contactor's functionality, and check the hybrid/EV battery control module for faults.

6. What repairs are needed to fix the P0AA4 code in a Chevrolet?

Repairs may include replacing a faulty battery contactor, repairing or replacing damaged wiring, replacing a defective relay, or reprogramming or replacing the hybrid/EV battery control module if necessary.

7. How much does it cost to repair the P0AA4 code in a Chevrolet?

The cost can vary widely, ranging from $200 to $1,500 or more depending on the specific issue, parts required, and labor costs.

8. Can the P0AA4 code be caused by a low 12-volt battery?

While unlikely, a weak or low 12-volt battery could potentially interfere with the hybrid/EV systemâ€™s diagnostic process, so itâ€™s important to confirm the 12-volt battery is in good condition.

9. How can I prevent the P0AA4 code from occurring in my Chevrolet?

Regular maintenance, ensuring proper operation of the high-voltage system, and promptly addressing warning lights or unusual vehicle behavior can help prevent this code.

10. Does the P0AA4 code require specialized tools to fix?

Yes, specialized tools such as a high-voltage safety tester, scan tool, and appropriate personal protective equipment (PPE) are typically required to safely diagnose and repair this issue.