AutoCodes – Chevrolet – P1B78 Chevrolet

P1B78 Chevrolet 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 Chevrolet 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 989

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 Chevrolet 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 Chevrolet - Hybrid/Electric Vehicle Battery 50 Circuit Performance - AutoCodes.com — P1B78 Chevrolet Code - Hybrid/Electric Vehicle Battery 50 Circuit Performance

What does this mean?

What are the Possible Causes of the DTC P1B78 Chevrolet?

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

How to Fix the DTC P1B78 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 P1B78 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 P1B78 Chevrolet Code

What does the OBDII code P1B78 mean on a Chevrolet?

1. P1B78 indicates an issue with the performance of the Hybrid/Electric Vehicle Battery 50 Circuit, which monitors specific battery functions in hybrid or electric Chevrolet vehicles. 2.

What are the common symptoms of a P1B78 code?

Symptoms may include an illuminated check engine light, reduced hybrid or electric vehicle performance, limited battery charging or discharging, or the vehicle entering limp mode. 3.

What causes the P1B78 code to appear?

This code can be caused by a faulty battery sensor, wiring or connector issues in the battery circuit, a damaged hybrid battery module, or a malfunctioning powertrain control module (PCM). 4.

Can I drive my Chevrolet with a P1B78 code?

It is not recommended to drive the vehicle for an extended period with this code, as it may lead to further damage to the hybrid battery system or reduced vehicle performance. 5.

How is the P1B78 code diagnosed?

A technician will use a scan tool to verify the code, inspect the battery circuit wiring and connectors, test the battery sensor, and possibly perform a battery module evaluation. 6.

What repairs are needed to fix the P1B78 code?

Repairs may include replacing faulty sensors, repairing or replacing damaged wiring or connectors, or addressing issues with the hybrid battery module or PCM. 7.

How much does it cost to fix a P1B78 code?

Repair costs vary depending on the cause but may range from $200 for wiring repairs to over $1,000 if the hybrid battery module requires replacement. 8.

Can a weak 12V battery cause the P1B78 code?

While uncommon, a weak 12V battery can sometimes contribute to hybrid system issues. It should be checked as part of the diagnostic process. 9.

How can I prevent the P1B78 code from occurring?

Regular maintenance of the vehicleâ€™s hybrid system, including inspecting battery connections and ensuring proper cooling of the battery pack, can help prevent this code. 10.

Does the P1B78 code reset itself after repairs?

In most cases, the code will need to be cleared using an OBDII scan tool after the underlying issue is resolved.