AutoCodes – Buick – P1B56 Buick

P1B56 Buick Code - Hybrid/Electric Vehicle Battery 38 Circuit High 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: P1B56 Buick indicates Hybrid/Electric Vehicle Battery 38 Circuit High 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 919

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 P1B56 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 P1B56 Buick - Hybrid/Electric Vehicle Battery 38 Circuit High Voltage - AutoCodes.com — P1B56 Buick Code - Hybrid/Electric Vehicle Battery 38 Circuit High Voltage

What does this mean?

What are the Possible Causes of the DTC P1B56 Buick?

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

How to Fix the DTC P1B56 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 P1B56 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 P1B56 Buick Code

1. What does OBDII code P1B56 mean on a Buick?

Code P1B56 indicates a high voltage issue in the Hybrid/Electric Vehicle Battery 38 Circuit, typically specific to GM hybrid or electric vehicles.

2. What are the common symptoms of a P1B56 code?

Symptoms may include warning lights on the dashboard, reduced hybrid or electric performance, and possibly a failure to start in electric mode.

3. What causes the P1B56 code to appear?

Possible causes include a faulty high-voltage battery cell, damaged wiring or connectors in the Battery 38 Circuit, or a malfunctioning battery management system.

4. Can driving with a P1B56 code damage my Buick?

Yes, continuing to drive without addressing the issue can damage the high-voltage battery or other hybrid system components.

5. How is the P1B56 code diagnosed?

Technicians use a scan tool to read the code and check live data. They may inspect the battery cells, wiring, and connectors for physical damage or irregular voltage readings.

6. What repairs can fix the P1B56 code?

Repairs may include replacing or repairing damaged wiring, connectors, or high-voltage battery components, or reprogramming the battery management system.

7. Is the P1B56 code covered under warranty?

High-voltage battery components often have extended warranties, so itâ€™s worth checking with your Buick dealer.

8. Can a low 12-volt battery cause the P1B56 code?

While unlikely, a weak 12-volt battery can sometimes cause communication issues within the hybrid system, leading to false codes.

9. How much does it cost to fix the P1B56 code on a Buick?

Repair costs vary widely depending on the issue but can range from $200 for wiring repairs to several thousand dollars for high-voltage battery replacement.

10. Can I clear the P1B56 code without repairs?

Clearing the code with a scan tool may temporarily remove it, but the issue will likely return unless the root cause is addressed.