AutoCodes – Buick – P0B42 Buick

P0B42 Buick Code - Hybrid/Electric Vehicle Battery 2 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: P0B42 Buick indicates Hybrid/Electric Vehicle Battery 2 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 1,296

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 P0B42 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 P0B42 Buick - Hybrid/Electric Vehicle Battery 2 Circuit Low Voltage - AutoCodes.com — P0B42 Buick Code - Hybrid/Electric Vehicle Battery 2 Circuit Low Voltage

What does this mean?

What are the Possible Causes of the DTC P0B42 Buick?

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

How to Fix the DTC P0B42 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 P0B42 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 P0B42 Buick Code

1. What does the OBDII code P0B42 mean on a Buick?

P0B42 indicates a "Hybrid/Electric Vehicle Battery 2 Circuit Low Voltage," meaning the vehicle's control module has detected a low voltage issue in the second battery circuit of the hybrid or electric system.

2. What are the common symptoms of P0B42 in a Buick?

Common symptoms include reduced fuel efficiency, limited electric-only driving range, warning lights on the dashboard, and potential loss of hybrid system functionality.

3. What causes the P0B42 code in a Buick?

The code can be caused by a malfunctioning battery module, faulty wiring or connectors in the battery circuit, a failed battery control module, or internal battery pack degradation.

4. Can I drive my Buick with a P0B42 code?

Driving with a P0B42 code is not recommended, as it can lead to further damage to the hybrid battery system or cause the vehicle to enter a limp mode, reducing performance.

5. How is the P0B42 code diagnosed?

A technician will use a scan tool to read the code, inspect the battery pack and wiring, check for loose or corroded connections, and test the voltage levels of the affected battery module.

6. What repairs are commonly needed to fix a P0B42 code?

Repairs may include replacing the affected battery module, repairing or replacing damaged wiring or connectors, or reprogramming the battery control module if necessary.

7. How much does it cost to fix the P0B42 code on a Buick?

Repair costs vary depending on the issue but can range from $200 for minor wiring repairs to over $2,000 for battery module replacement.

8. Can a weak 12-volt battery cause the P0B42 code?

While unlikely, a weak 12-volt battery can sometimes cause hybrid system faults. Itâ€™s recommended to check the 12-volt battery health as part of the diagnostic process.

9. How can I prevent the P0B42 code from occurring in my Buick?

Regular maintenance of the hybrid battery system, checking for loose or corroded connections, and addressing warning signs early can help prevent the P0B42 code.

10. Does the P0B42 code automatically mean my hybrid battery needs replacement?

Not necessarily. The issue could be due to wiring, connectors, or the control module. A thorough diagnosis is essential to pinpoint the root cause.