AutoCodes – Buick – P1EFA Buick

P1EFA Buick Code - Battery Charger High-Voltage Converter 1 Input Current Too High

Quick Answer

The hybrid/EV powertrain control module 2 monitors the battery charger high-voltage output and current output and ensures they are within the proper range. Common causes include Faulty Battery Charger, Battery Charger harness is open or shorted, Battery Charger 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: P1EFA Buick indicates Battery Charger High-Voltage Converter 1 Input Current Too High.
Common causes: Common causes include Faulty Battery Charger, Battery Charger harness is open or shorted, Battery Charger 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 856

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 25, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P1EFA Buick Description

The hybrid/EV powertrain control module 2 monitors the battery charger high-voltage output and current output and ensures they are within the proper range. The battery charger operates in either a constant current mode or a constant voltage mode. Whichever mode you are in will determine which diagnostic will be run. The battery charger runs constant voltage mode at the beginning and end of the charge cycle and runs constant current mode most of the charging cycle.

OBDII Code P1EFA Buick - Battery Charger High-Voltage Converter 1 Input Current Too High - AutoCodes.com — P1EFA Buick Code - Battery Charger High-Voltage Converter 1 Input Current Too High

What does this mean?

What are the Possible Causes of the DTC P1EFA Buick?

Faulty Battery Charger
Battery Charger harness is open or shorted
Battery Charger circuit poor electrical connection

How to Fix the DTC P1EFA Buick?

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 P1EFA Buick 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 P1EFA Buick Code

1. What does the OBDII code P1EFA mean on a Buick?

The P1EFA code indicates that the Battery Charger High-Voltage Converter 1 is detecting an input current that is too high, which may interfere with proper charging or vehicle operation.

2. What are the common symptoms of code P1EFA in a Buick?

Symptoms may include a check engine light, charging system warnings, reduced vehicle performance, or failure of the high-voltage battery to charge properly.

3. What causes the P1EFA code to appear in a Buick?

Common causes include a faulty high-voltage converter, wiring or connector issues, a defective battery charger, or an electrical short in the high-voltage system.

4. Can a bad high-voltage battery cause the P1EFA code?

While rare, a malfunctioning high-voltage battery can contribute to the code if it places excessive demand on the converter or if there is an internal fault.

5. How is the P1EFA code diagnosed?

A technician will use a scan tool to verify the code, inspect the wiring and connectors for damage, test the high-voltage converter, and check the battery charger functionality.

6. Can I drive my Buick with the P1EFA code?

Driving with this code is not recommended, as it can lead to further electrical damage, charging system failure, or reduced vehicle performance.

7. How much does it cost to repair the P1EFA code in a Buick?

Repair costs vary depending on the root cause, but it can range from $200 for simple wiring repairs to over $1,000 for replacing the high-voltage converter or charger.

8. Can I fix the P1EFA code myself?

If you have advanced automotive electrical knowledge, you can inspect the wiring and connectors. However, diagnosing and repairing high-voltage systems is best left to a professional due to safety risks.

9. Will clearing the code fix the P1EFA issue?

Clearing the code may temporarily turn off the check engine light, but the underlying issue must be repaired to prevent the code from returning.

10. What tools are required to address the P1EFA code?

Proper diagnosis and repair require an advanced scan tool, a multimeter for electrical testing, and potentially specialized equipment for high-voltage systems.