AutoCodes – Cadillac – P1B51 Cadillac

P1B51 Cadillac Code - Hybrid/Electric Vehicle Battery 37 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: P1B51 Cadillac indicates Hybrid/Electric Vehicle Battery 37 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 911

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 09, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P1B51 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 P1B51 Cadillac - Hybrid/Electric Vehicle Battery 37 Circuit Low Voltage - AutoCodes.com — P1B51 Cadillac Code - Hybrid/Electric Vehicle Battery 37 Circuit Low Voltage

What does this mean?

What are the Possible Causes of the DTC P1B51 Cadillac?

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

How to Fix the DTC P1B51 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 P1B51 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 P1B51 Cadillac Code

1. What are common symptoms of OBDII code P1B51 in a Cadillac Hybrid/Electric Vehicle?

- Common symptoms may include reduced battery performance, difficulty starting the vehicle, and the illumination of the check engine light.

2. What can cause the OBDII code P1B51 in a Cadillac Hybrid/Electric Vehicle?

- The code P1B51 typically indicates a low voltage condition in the hybrid/electric vehicle battery 37 circuit, which can be caused by a faulty battery module, poor electrical connections, or issues with the battery management system.

3. How can I diagnose the OBDII code P1B51 in my Cadillac Hybrid/Electric Vehicle?

- Diagnosing the code P1B51 may involve using a scan tool to retrieve the specific fault codes, testing the battery voltage and connections, and inspecting the battery components for any visible damage.

4. What are the potential risks of driving with the OBDII code P1B51 in a Cadillac Hybrid/Electric Vehicle?

- Driving with the code P1B51 can lead to further damage to the hybrid/electric vehicle battery system, reduced fuel efficiency, and potential safety hazards due to unreliable battery performance.

5. Can I repair the OBDII code P1B51 in my Cadillac Hybrid/Electric Vehicle myself?

- While some basic troubleshooting steps can be taken, it is recommended to seek professional assistance for diagnosing and repairing the code P1B51 to ensure the proper handling of high-voltage components.

6. How much does it typically cost to repair the OBDII code P1B51 in a Cadillac Hybrid/Electric Vehicle?

- The cost of repairing the code P1B51 can vary depending on the underlying cause and the extent of the repairs needed. It is advisable to consult with a qualified technician for an accurate diagnosis and cost estimate.

7. Are there any preventive maintenance tips to avoid the OBDII code P1B51 in a Cadillac Hybrid/Electric Vehicle?

- Regularly inspecting the hybrid/electric vehicle battery system, maintaining proper charging habits, and following the manufacturer's recommended service schedule can help prevent issues that may trigger the code P1B51.

8. What are the potential long-term effects of ignoring the OBDII code P1B51 in a Cadillac Hybrid/Electric Vehicle?

- Ignoring the code P1B51 can lead to progressive deterioration of the battery system, increased risk of complete battery failure, and potentially costly repairs or replacements in the future.

9. Can the OBDII code P1B51 be triggered by extreme weather conditions in a Cadillac Hybrid/Electric Vehicle?

- Extreme temperatures, both hot and cold, can affect the performance of the hybrid/electric vehicle battery system and potentially trigger the code P1B51. It is important to monitor battery health and take appropriate precautions in such conditions.

10. Is it safe to continue driving my Cadillac Hybrid/Electric Vehicle with the OBDII code P1B51 temporarily cleared?

- Clearing the code P1B51 may temporarily reset the check engine light, but it is not recommended to continue driving the vehicle without addressing the underlying issue, as it can lead to further complications and potential safety risks.