AutoCodes – Cadillac – P0B51 Cadillac

P0B51 Cadillac Code - Hybrid/Electric Vehicle Battery 5 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: P0B51 Cadillac indicates Hybrid/Electric Vehicle Battery 5 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 1,024

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 07, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P0B51 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 P0B51 Cadillac - Hybrid/Electric Vehicle Battery 5 Circuit Low Voltage - AutoCodes.com — P0B51 Cadillac Code - Hybrid/Electric Vehicle Battery 5 Circuit Low Voltage

What does this mean?

What are the Possible Causes of the DTC P0B51 Cadillac?

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

How to Fix the DTC P0B51 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 P0B51 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 P0B51 Cadillac Code

1. What are the common symptoms of OBDII code P0B51 in a Cadillac Hybrid/Electric Vehicle?

- The common symptoms include reduced fuel efficiency, decreased power output, and potential issues with the vehicle's hybrid/electric system.

2. What are the possible causes of OBDII code P0B51 indicating Hybrid/Electric Vehicle Battery 5 Circuit Low Voltage in a Cadillac?

- The code may be triggered by a faulty battery cell, damaged wiring, a failing battery management system, or issues with the hybrid/electric vehicle's charging system.

3. How can I diagnose OBDII code P0B51 in my Cadillac Hybrid/Electric Vehicle?

- A diagnostic scan tool can help identify the specific location of the issue within the battery system. Additionally, visual inspection of the battery components and wiring may provide valuable insights.

4. Can driving with OBDII code P0B51 present in a Cadillac Hybrid/Electric Vehicle cause further damage?

- Continuing to drive with this code present can potentially lead to further damage to the hybrid/electric battery system and may result in decreased performance and reliability.

5. What are some repair tips for addressing OBDII code P0B51 in a Cadillac Hybrid/Electric Vehicle?

- It is recommended to have a professional technician inspect and test the battery system to pinpoint the exact cause of the low voltage issue. Repairs may involve replacing damaged battery cells, repairing faulty wiring, or recalibrating the battery management system.

6. Is it safe to reset the OBDII code P0B51 in a Cadillac Hybrid/Electric Vehicle without addressing the underlying issue?

- While resetting the code may temporarily clear the warning light, it is essential to address the root cause of the low voltage issue to prevent potential long-term damage to the hybrid/electric vehicle's battery system.

7. How can regular maintenance help prevent OBDII code P0B51 from appearing in a Cadillac Hybrid/Electric Vehicle?

- Regularly scheduled maintenance, including battery system checks and software updates, can help prevent issues that may trigger the P0B51 code, ensuring optimal performance and longevity of the hybrid/electric vehicle.

8. Can extreme weather conditions impact the occurrence of OBDII code P0B51 in a Cadillac Hybrid/Electric Vehicle?

- Yes, extreme temperatures can affect the performance of the hybrid/electric vehicle battery system, potentially leading to low voltage issues that trigger the P0B51 code. Proper insulation and temperature management can help mitigate these effects.

9. Are there any recalls or technical service bulletins related to OBDII code P0B51 in Cadillac Hybrid/Electric Vehicles?

- It is advisable to check with the manufacturer or authorized service centers for any recalls or technical bulletins related to the P0B51 code to stay informed about potential known issues and remedies.

10. How can I ensure the proper functioning of the hybrid/electric vehicle battery system to avoid triggering OBDII code P0B51 in a Cadillac?

- Regularly monitoring the battery system's health, following recommended maintenance schedules, and addressing any warning signs promptly can help maintain the proper functioning of the hybrid/electric vehicle battery system and prevent the occurrence of the P0B51 code.