AutoCodes – Cadillac – P1B91 Cadillac

P1B91 Cadillac 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 Cadillac 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 993

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

What does this mean?

What are the Possible Causes of the DTC P1B91 Cadillac?

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

How to Fix the DTC P1B91 Cadillac?

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 Cadillac 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 Cadillac Code

1. What are the common symptoms of OBDII code P1B91 in a Cadillac Hybrid/Electric Vehicle?

- Common symptoms include reduced electric vehicle range, poor performance, and potential issues with starting the vehicle.

2. What can cause the Hybrid/Electric Vehicle Battery 58 Circuit Low Voltage code (P1B91) in a Cadillac?

- Possible causes include a weak or failing hybrid/electric vehicle battery, issues with the battery management system, or a fault in the battery voltage sensor.

3. How serious is the P1B91 code on a Cadillac Hybrid/Electric Vehicle?

- The P1B91 code indicating low voltage in the hybrid/electric vehicle battery is a serious issue that can affect the performance and efficiency of the vehicle. It should be addressed promptly to prevent further damage.

4. Can I continue driving my Cadillac with the P1B91 code present?

- It is not recommended to continue driving the vehicle with the P1B91 code, as low voltage in the hybrid/electric vehicle battery can lead to further damage and potential safety hazards.

5. What are some DIY repair tips for addressing the P1B91 code in a Cadillac Hybrid/Electric Vehicle?

- DIY repair tips may include checking the battery connections, ensuring the battery is charged properly, and inspecting for any visible damage or corrosion in the battery components.

6. How can I reset the OBDII code P1B91 in my Cadillac to see if it returns?

- You can reset the OBDII code P1B91 using an OBDII scanner or by disconnecting the vehicle's battery for a few minutes. However, if the underlying issue is not addressed, the code is likely to return.

7. Is it safe to attempt to clear the P1B91 code by disconnecting the battery in a Cadillac Hybrid/Electric Vehicle?

- Disconnecting the battery to clear the code is generally safe, but it is important to follow proper procedures to avoid damaging any electrical components. It is recommended to consult a professional if unsure.

8. How can a professional mechanic diagnose the specific cause of the P1B91 code in a Cadillac Hybrid/Electric Vehicle?

- A professional mechanic can use specialized diagnostic tools to test the hybrid/electric vehicle battery, inspect the battery management system, and analyze the voltage sensor readings to pinpoint the exact cause of the code.

9. What are the potential repair costs associated with fixing the Hybrid/Electric Vehicle Battery 58 Circuit Low Voltage code in a Cadillac?

- Repair costs can vary depending on the specific issue causing the P1B91 code. Costs may include battery replacement, sensor repairs, or addressing issues with the battery management system, which can range from a few hundred to several thousand dollars.

10. How often should I have the hybrid/electric vehicle battery system inspected to prevent issues like the P1B91 code in a Cadillac?

- It is recommended to have the hybrid/electric vehicle battery system inspected as part of regular maintenance, typically every 1-2 years or as advised in the vehicle's manual, to prevent issues and ensure optimal performance.