AutoCodes – Generic – P1E79

P1E79 Code - Hybrid/Electric Vehicle Battery 78 Circuit

Quick Answer

The Hybrid/Electric Vehicle battery pack contains 288 cells. Common causes include Faulty Hybrid/Electric Vehicle Battery Pack, Faulty Hybrid/Electric Vehicle Battery Interface Control Module. 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: P1E79 indicates Hybrid/Electric Vehicle Battery 78 Circuit.
Common causes: Common causes include Faulty Hybrid/Electric Vehicle Battery Pack, Faulty Hybrid/Electric Vehicle Battery Interface Control Module.
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 804

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 Mar 14, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P1E79 Description

The Hybrid/Electric Vehicle battery pack contains 288 cells. Groups of three cells are welded together in parallel. There are a total of 96 cell groups in the hybrid/EV battery pack assembly. These cell groups are electrically connected in-series. Each individual cell group is rated at 3.7 V, for a nominal system voltage of 355 V direct current. The battery cells are also grouped together into three sections. The first 90 cells/30 cell groups make up battery section one. This section is adjacent to the cowl and contains batteries 67 through to 96. Battery section two is located behind section one. It is made up of 72 cells/24 cell groups and contains batteries 43 through to 66. The transverse battery section is section number three, it is made up of the remaining 126 cells/42 cell groups and contains batteries 1 through to 42. The three battery sections are individually serviceable components.
The battery energy control module monitors the voltage of the 96 battery cell groups through the four hybrid/EV battery interface control modules. Voltage sense circuits are attached to each individual cell group, and these sense circuits terminate at a connector located on the top surface of the battery section. A serviceable auxiliary battery wiring harness joins this connector to a hybrid/EV battery interface control module, also located on the top surface of the battery section. The hybrid/EV battery interface control module encodes the voltage reading and transmits it to the battery energy control module through the battery control harness. There is one hybrid/EV battery interface control module located on battery sections one and two, and two hybrid/EV battery interface control modules associated with battery section three. The hybrid/EV battery interface control module, battery energy control module wiring harness, auxiliary battery wiring harness, and battery energy control module are all considered serviceable components.
The battery energy control module will determine when a fault condition is present. Diagnostics and system status are communicated from the battery energy control module to hybrid/EV powertrain control module 2 through serial data. The hybrid/EV powertrain control module 2 is the host controller for diagnostic trouble code information.

OBDII Code P1E79 - Hybrid/Electric Vehicle Battery 78 Circuit - AutoCodes.com — P1E79 Code - Hybrid/Electric Vehicle Battery 78 Circuit

What does this mean?

What are the Possible Causes of the DTC P1E79?

Faulty Hybrid/Electric Vehicle Battery Pack
Faulty Hybrid/Electric Vehicle Battery Interface Control Module

How to Fix the DTC P1E79?

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 P1E79 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 P1E79 code?

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Need Help with the Code?

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Information for Specific Makes

P1E79 Buick — Hybrid/Electric Vehicle Battery 78 Circuit
P1E79 Cadillac — Hybrid/Electric Vehicle Battery 78 Circuit
P1E79 Chevrolet — Hybrid/Electric Vehicle Battery 78 Circuit
P1E79 GMC — Hybrid/Electric Vehicle Battery 78 Circuit
P1E79 Saturn — Hybrid/Electric Vehicle Battery 78 Circuit

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 P1E79 Code

1. What does the OBDII code P1E79 mean?

P1E79 indicates an issue with the "Hybrid/Electric Vehicle Battery 78 Circuit," which typically points to a problem in the battery's monitoring or control system.

2. What are the common symptoms of code P1E79?

Symptoms may include a check engine light, reduced hybrid or EV performance, limited driving range, or the vehicle entering a limp mode.

3. What causes the P1E79 code to appear?

Common causes include faulty battery sensors, wiring issues in the battery circuit, a malfunctioning battery control module, or a degraded hybrid/EV battery.

4. Can I drive my car with the P1E79 code?

While you may still be able to drive, itâ€™s not recommended as it could lead to further damage or reduced performance. Have the issue diagnosed and repaired promptly.

5. How is the P1E79 code diagnosed?

A technician will use a scan tool to read the code and check for related codes, perform a visual inspection of the battery circuit wiring and connectors, and test the battery and control module.

6. What repairs can fix the P1E79 code?

Repairs may include replacing damaged wiring or connectors, replacing the battery control module, or in some cases, replacing the hybrid/EV battery.

7. Can a low or discharged battery trigger the P1E79 code?

Yes, a low or discharged hybrid/EV battery can sometimes trigger this code. Ensure the battery is charged and functioning properly.

8. How much does it cost to fix the P1E79 code?

Repair costs vary widely depending on the issue. Simple wiring repairs may cost $100-$300, while battery control module or battery replacement can cost significantly more, often exceeding $1,000.

9. Can I reset the P1E79 code myself?

You can clear the code with an OBDII scanner, but if the underlying issue isnâ€™t resolved, the code will likely return.

10. Is the P1E79 code specific to any vehicle make or model?

This code is most commonly found in hybrid and electric vehicles, but specific diagnostic and repair procedures may vary by manufacturer. Always refer to your vehicleâ€™s service manual.