AutoCodes – Generic – P1B78

P1B78 Code - Hybrid/Electric Vehicle Battery 50 Circuit Performance

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: P1B78 indicates Hybrid/Electric Vehicle Battery 50 Circuit Performance.
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 1,704

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 12, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P1B78 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 P1B78 - Hybrid/Electric Vehicle Battery 50 Circuit Performance - AutoCodes.com — P1B78 Code - Hybrid/Electric Vehicle Battery 50 Circuit Performance

What does this mean?

What are the Possible Causes of the DTC P1B78?

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

How to Fix the DTC P1B78?

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 P1B78 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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Need Help with the Code?

Get the P1B78 code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

P1B78 Buick — Hybrid/Electric Vehicle Battery 50 Circuit Performance
P1B78 Cadillac — Hybrid/Electric Vehicle Battery 50 Circuit Performance
P1B78 Chevrolet — Hybrid/Electric Vehicle Battery 50 Circuit Performance
P1B78 GMC — Hybrid/Electric Vehicle Battery 50 Circuit Performance
P1B78 Saturn — Hybrid/Electric Vehicle Battery 50 Circuit Performance

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 P1B78 Code

1. What are common symptoms of OBDII code P1B78 (Hybrid/Electric Vehicle Battery 50 Circuit Performance)?

- Common symptoms include reduced electric vehicle range, poor battery performance, and warning lights on the dashboard.

2. What are some possible causes of OBDII code P1B78?

- Possible causes include a malfunctioning battery pack, issues with the battery management system, damaged wiring, or a faulty sensor.

3. How can I diagnose OBDII code P1B78?

- Diagnosis typically involves using a diagnostic scanner to read the code, testing the battery voltage, inspecting the battery connections, and checking for any visible damage.

4. Can I still drive my vehicle with OBDII code P1B78?

- It is not recommended to continue driving the vehicle with this code as it can lead to further damage to the battery system and potentially unsafe driving conditions.

5. How can I repair OBDII code P1B78?

- Repair options may include replacing the battery pack, repairing damaged wiring, resetting the battery management system, or seeking professional help from a qualified technician.

6. Is it safe to reset the OBDII code P1B78 and continue driving?

- It is not recommended to reset the code without addressing the underlying issue, as this may lead to temporary relief but the problem will likely resurface.

7. How can I prevent OBDII code P1B78 from occurring in the future?

- Regular maintenance of the hybrid/electric vehicle battery system, monitoring battery performance, and addressing any warning signs promptly can help prevent this code from occurring.

8. Is OBDII code P1B78 a serious issue?

- Yes, OBDII code P1B78 indicates a performance issue with the hybrid/electric vehicle battery circuit, which can affect the vehicle's overall efficiency and safety.

9. Can a DIY enthusiast fix OBDII code P1B78 at home?

- While some basic checks and repairs can be done at home, diagnosing and repairing complex issues related to the hybrid/electric vehicle battery system may require specialized knowledge and tools.

10. How much does it cost to repair OBDII code P1B78?

- The cost of repair can vary depending on the underlying issue, parts needed, and labor costs. It is recommended to consult a professional for an accurate estimate.