AutoCodes – Chevrolet – P1B91 Chevrolet

P1B91 Chevrolet Code - Hybrid/Electric Vehicle Battery 58 Circuit Low Voltage

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: P1B91 Chevrolet indicates Hybrid/Electric Vehicle Battery 58 Circuit Low Voltage.
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 1,121

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 P1B91 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 P1B91 Chevrolet - Hybrid/Electric Vehicle Battery 58 Circuit Low Voltage - AutoCodes.com — P1B91 Chevrolet Code - Hybrid/Electric Vehicle Battery 58 Circuit Low Voltage

What does this mean?

What are the Possible Causes of the DTC P1B91 Chevrolet?

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

How to Fix the DTC P1B91 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 P1B91 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 P1B91 Chevrolet Code

1. What does the OBDII code P1B91 mean on a Chevrolet?

P1B91 indicates a "Hybrid/Electric Vehicle Battery 58 Circuit Low Voltage," meaning the voltage in circuit 58 of the hybrid battery is lower than expected.

2. What are the common symptoms of the P1B91 code on a Chevrolet?

Symptoms may include reduced hybrid system performance, illuminated check engine light, warning messages on the dashboard, and possible decreased fuel efficiency.

3. What causes the P1B91 code to appear?

Common causes include a faulty hybrid battery cell, damaged wiring or connectors in circuit 58, a defective battery control module, or internal electrical faults.

4. Can I drive my Chevrolet with the P1B91 code?

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

5. How do technicians diagnose the P1B91 code?

Technicians use a scan tool to read the code, inspect the hybrid battery and related wiring, and perform voltage tests on circuit 58 to identify faults.

6. How is the P1B91 code fixed on a Chevrolet?

Repairs may involve replacing damaged wiring or connectors, repairing or replacing the hybrid battery, or reprogramming or replacing the battery control module.

7. How much does it cost to fix the P1B91 code on a Chevrolet?

Repair costs can range from $200 for minor wiring repairs to over $3,000 for hybrid battery replacement, depending on the severity of the issue.

8. Can a weak 12V battery cause the P1B91 code?

While the 12V battery is separate from the hybrid battery, issues with it can sometimes cause related electrical problems, so it should be inspected as part of the diagnosis.

9. Is the P1B91 code covered under warranty?

If your Chevrolet is still under the hybrid or powertrain warranty, the repairs for P1B91 may be covered. Check with your dealership for specific details.

10. Can I clear the P1B91 code and continue driving?

Clearing the code without addressing the underlying issue will likely cause the problem to return and could result in further damage over time.