AutoCodes – Buick – P1B4A Buick

P1B4A Buick Code - Hybrid/Electric Vehicle Battery 34 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: P1B4A Buick indicates Hybrid/Electric Vehicle Battery 34 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 784

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 08, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P1B4A 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 P1B4A Buick - Hybrid/Electric Vehicle Battery 34 Circuit High Voltage - AutoCodes.com — P1B4A Buick Code - Hybrid/Electric Vehicle Battery 34 Circuit High Voltage

What does this mean?

What are the Possible Causes of the DTC P1B4A Buick?

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

How to Fix the DTC P1B4A 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 P1B4A 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 P1B4A Buick Code

1. What does the OBDII code P1B4A mean on a Buick?

The P1B4A code indicates an issue with the Hybrid/Electric Vehicle Battery 34 Circuit, specifically detecting high voltage in the circuit.

2. What are the common symptoms of code P1B4A on a Buick?

Symptoms may include an illuminated check engine light, reduced hybrid/electric vehicle performance, limited battery charging, or the vehicle entering limp mode.

3. What causes the P1B4A code to appear?

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

4. Can I continue driving with a P1B4A code on my Buick?

Itâ€™s not recommended to drive for extended periods with this code, as it may lead to reduced performance or further damage to the hybrid system.

5. How do I diagnose the P1B4A code on my Buick?

Diagnosis involves inspecting the hybrid battery, checking for damaged or corroded wiring and connectors, and testing the battery control module for faults.

6. What repairs are needed to fix the P1B4A code?

Repairs may include replacing the faulty hybrid battery module, repairing or replacing damaged wiring, or reprogramming or replacing the battery control module.

7. How much does it cost to fix the P1B4A code on a Buick?

Repair costs vary but can range from $200 for minor wiring repairs to $4,000 or more if the hybrid battery needs replacement.

8. Can a low 12V battery cause the P1B4A code?

While a low 12V battery is unlikely to directly cause this code, it can create battery control module issues, which may indirectly trigger the code.

9. Does the P1B4A code require a dealer to fix?

Not necessarily, but hybrid system repairs often require specialized tools and knowledge, so consulting a dealership or qualified hybrid technician is recommended.

10. Can ignoring the P1B4A code damage my Buick?

Yes, ignoring this code can lead to further hybrid system damage, reduced fuel efficiency, or even complete vehicle shutdown in severe cases.