AutoCodes – Buick – P1EFC Buick

P1EFC Buick Code - Battery Charger Control Module System Voltage Low Voltage

Quick Answer

The vehicle control modules or sensors monitor the system voltage to verify the system voltage is within the normal operating range. Common causes include Faulty Battery Charger Control Module, Battery Charger Control Module harness is open or shorted, Battery Charger 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: P1EFC Buick indicates Battery Charger Control Module System Voltage Low Voltage.
Common causes: Common causes include Faulty Battery Charger Control Module, Battery Charger Control Module harness is open or shorted, Battery Charger 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 833

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 P1EFC Buick Description

The vehicle control modules or sensors monitor the system voltage to verify the system voltage is within the normal operating range. The Powertrain Control Module (PCM) sets the OBDII code when the Battery Charger Control Module is not to factory specifications.

OBDII Code P1EFC Buick - Battery Charger Control Module System Voltage Low Voltage - AutoCodes.com — P1EFC Buick Code - Battery Charger Control Module System Voltage Low Voltage

What does this mean?

What are the Possible Causes of the DTC P1EFC Buick?

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

How to Fix the DTC P1EFC 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 P1EFC 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.

Need more information about the P1EFC Buick code?

Need more information on how to fix the P1EFC Buick code? Get Access to Factory Service Manuals

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Get the P1EFC Buick code diagnosed by a professional: Find a repair shop in your area

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 P1EFC Buick Code

1. What does the OBDII code P1EFC mean on a Buick?

P1EFC indicates that the Battery Charger Control Module has detected a low system voltage condition.

2. What are the common symptoms of the P1EFC code in a Buick?

Symptoms may include warning lights on the dashboard, difficulty starting the vehicle, reduced charging performance, or issues with hybrid or electric system functionality.

3. What causes the P1EFC code to appear on a Buick?

Common causes include a faulty Battery Charger Control Module, damaged wiring or connectors, a weak or failing 12V battery, or issues with the high-voltage battery system.

4. Can a weak 12V battery trigger the P1EFC code?

Yes, a weak or failing 12V battery can cause low system voltage, which may trigger the P1EFC code.

5. How can I diagnose the P1EFC code on my Buick?

Start by checking the 12V batteryâ€™s condition and voltage, inspecting the wiring and connections to the Battery Charger Control Module, and using a scan tool to monitor system voltages and module communication.

6. Is it safe to drive a Buick with the P1EFC code?

It is not recommended to drive with the P1EFC code, as it may indicate issues with the charging system that could lead to reduced performance or failure of the vehicle's hybrid/electric systems.

7. How is the P1EFC code typically repaired?

Repairs may include replacing the 12V battery, repairing or replacing damaged wiring or connectors, reprogramming or replacing the Battery Charger Control Module, or addressing issues with the high-voltage battery system.

8. Can a software update fix the P1EFC code?

In some cases, a software update for the Battery Charger Control Module may resolve the issue if itâ€™s caused by a programming error.

9. How much does it cost to fix the P1EFC code on a Buick?

Repair costs can vary widely depending on the root cause. Replacing a 12V battery may cost $100-$250, while replacing or reprogramming the Battery Charger Control Module can cost $500-$1,500.

10. What tools are needed to troubleshoot the P1EFC code?

Youâ€™ll need a multimeter to check voltage levels, a scan tool capable of reading manufacturer-specific codes and data, and wiring diagrams to inspect electrical connections.