AutoCodes – Buick – P1B51 Buick

P1B51 Buick 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 Buick 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 883

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 Buick 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 Buick - Hybrid/Electric Vehicle Battery 37 Circuit Low Voltage - AutoCodes.com — P1B51 Buick Code - Hybrid/Electric Vehicle Battery 37 Circuit Low Voltage

What does this mean?

What are the Possible Causes of the DTC P1B51 Buick?

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

How to Fix the DTC P1B51 Buick?

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 Buick 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 Buick Code

1. What does the OBDII code P1B51 mean on a Buick?

The code P1B51 indicates a "Hybrid/Electric Vehicle Battery 37 Circuit Low Voltage," meaning there is a low voltage issue in circuit 37 of the hybrid or EV battery system.

2. What are the common symptoms of code P1B51 in a Buick?

Symptoms may include an illuminated check engine light, reduced hybrid performance, limited electric-only mode, or diminished fuel efficiency.

3. What causes the P1B51 code to appear in a Buick hybrid or EV?

Common causes include a faulty hybrid battery cell, damaged wiring or connectors in the battery circuit, or a malfunctioning battery control module.

4. Can I drive my Buick with a P1B51 code?

While you may be able to drive the vehicle, it is not recommended as the hybrid system may not function correctly, potentially leading to further damage or reduced performance.

5. How is the P1B51 code diagnosed in a Buick?

A technician will use an OBDII scanner to confirm the code, inspect the battery circuit and wiring for damage, and test the voltage levels of the hybrid battery system.

6. What repairs are typically needed to fix code P1B51?

Repairs may include replacing damaged wires or connectors, repairing or replacing the hybrid battery pack, or reprogramming the battery control module.

7. How much does it cost to fix the P1B51 code on a Buick hybrid or EV?

Repair costs vary depending on the issue but can range from $100 for minor wiring repairs to over $1,000 if the battery or control module needs replacement.

8. Can a low 12-volt battery cause the P1B51 code in a Buick?

While a weak 12-volt battery can cause some electrical issues, this code specifically refers to the hybrid battery system, so the 12-volt battery is unlikely to be the root cause.

9. Is the P1B51 code common for Buick hybrid or electric vehicles?

This code is relatively uncommon and usually indicates a specific issue within the hybrid battery system, requiring prompt attention.

10. Can I clear the P1B51 code without repairs?

Clearing the code with an OBDII scanner may temporarily turn off the warning light, but the underlying problem will persist and likely cause the code to return.