AutoCodes – Generic – P1B91

P1B91 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 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 984

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

What does this mean?

What are the Possible Causes of the DTC P1B91?

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

How to Fix the DTC P1B91?

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 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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Information for Specific Makes

P1B91 Buick — Hybrid/Electric Vehicle Battery 58 Circuit Low Voltage
P1B91 Cadillac — Hybrid/Electric Vehicle Battery 58 Circuit Low Voltage
P1B91 Chevrolet — Hybrid/Electric Vehicle Battery 58 Circuit Low Voltage
P1B91 GMC — Hybrid/Electric Vehicle Battery 58 Circuit Low Voltage
P1B91 Saturn — Hybrid/Electric Vehicle Battery 58 Circuit Low Voltage

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 Code

1. What are the common symptoms of OBDII code P1B91 (Hybrid/Electric Vehicle Battery 58 Circuit Low Voltage)?

- Common symptoms include reduced electric vehicle range, difficulty starting the vehicle, and illuminated warning lights on the dashboard related to the battery system.

2. What are the possible causes of OBDII code P1B91?

- The code P1B91 can be caused by issues such as a faulty battery cell, poor electrical connections, damaged wiring, or a malfunctioning battery management system.

3. How can I diagnose the cause of OBDII code P1B91?

- Diagnosing the cause of P1B91 typically involves using a diagnostic scan tool to retrieve the code, checking the battery voltage levels, inspecting the battery connections and wiring, and performing a battery capacity test.

4. What are some repair tips for addressing OBDII code P1B91?

- Repair tips may include checking and tightening battery connections, repairing or replacing damaged wiring, inspecting the battery for any visible damage, and resetting the battery management system.

5. Is it safe to continue driving with OBDII code P1B91 present?

- It is not recommended to continue driving with code P1B91 present, as it can lead to further damage to the hybrid/electric vehicle's battery system and potentially cause safety hazards.

6. Can I reset OBDII code P1B91 myself?

- While you can attempt to reset the code using a diagnostic scan tool, it is important to address the underlying issue causing the code to prevent it from reoccurring.

7. How much does it typically cost to repair OBDII code P1B91?

- The cost of repairing OBDII code P1B91 can vary depending on the specific cause of the issue, but it may involve costs associated with parts replacement, labor, and diagnostic testing.

8. Can OBDII code P1B91 be a recurring issue?

- Yes, OBDII code P1B91 can be a recurring issue if the underlying cause is not properly diagnosed and repaired. Regular maintenance and monitoring of the hybrid/electric vehicle's battery system are essential to prevent reoccurrences.

9. Are there any preventative measures to avoid OBDII code P1B91?

- To help prevent OBDII code P1B91, it is important to maintain the hybrid/electric vehicle's battery system, follow recommended maintenance schedules, and address any electrical issues promptly.

10. Can OBDII code P1B91 be related to other vehicle problems?

- OBDII code P1B91 is specifically related to hybrid/electric vehicle battery circuit low voltage issues and may not be directly related to other vehicle problems, but it is essential to address this code promptly to avoid potential complications.