AutoCodes – Cadillac – P1B8B Cadillac

P1B8B Cadillac Code - Hybrid/Electric Vehicle Battery 56 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: P1B8B Cadillac indicates Hybrid/Electric Vehicle Battery 56 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 843

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 P1B8B 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 P1B8B Cadillac - Hybrid/Electric Vehicle Battery 56 Circuit Low Voltage - AutoCodes.com — P1B8B Cadillac Code - Hybrid/Electric Vehicle Battery 56 Circuit Low Voltage

What does this mean?

What are the Possible Causes of the DTC P1B8B Cadillac?

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

How to Fix the DTC P1B8B 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 P1B8B 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 P1B8B Cadillac Code

1. What does the OBDII code P1B8B mean on a Cadillac?

The P1B8B code indicates a "Hybrid/Electric Vehicle Battery 56 Circuit Low Voltage," meaning an issue with the voltage level in battery cell 56 or its circuit.

2. What are the symptoms of the P1B8B code in a Cadillac?

Common symptoms include decreased vehicle performance, warning lights on the dashboard (such as the check engine or hybrid system light), and possible failure to switch between electric and gas modes.

3. What causes the P1B8B code to appear?

The code can be triggered by a faulty hybrid battery cell, corroded or damaged wiring, poor connections in the battery circuit, or a malfunctioning battery control module.

4. Can I drive my Cadillac with the P1B8B code?

It's not recommended to drive with this code active, as it can lead to reduced performance and further damage to the hybrid battery or related components.

5. How is the P1B8B code diagnosed?

A technician will use a scan tool to confirm the code, inspect the battery control module, measure the voltages of individual battery cells, and check for damaged wiring or poor connections.

6. How do you fix the P1B8B code on a Cadillac?

Repairs may include replacing the faulty battery cell, repairing or replacing damaged wiring, cleaning corroded connections, or reprogramming/updating the battery control module.

7. Is the hybrid battery always the problem when the P1B8B code is present?

No, while the battery is a common cause, the issue could also stem from wiring, connectors, or the control module.

8. What tools are needed to repair the P1B8B code?

A diagnostic scan tool, multimeter, and appropriate safety equipment for handling high-voltage battery components are typically required.

9. How much does it cost to fix the P1B8B code?

Repair costs vary widely, ranging from $100 for minor wiring repairs to over $1,000 if the hybrid battery or control module needs replacement.

10. Can a low 12-volt battery cause the P1B8B code?

While the 12-volt battery is unlikely to cause this specific code, a weak 12-volt system can affect hybrid system diagnostics and should be checked as part of the troubleshooting process.