AutoCodes – Cadillac – P1B99 Cadillac

P1B99 Cadillac Code - Hybrid/Electric Vehicle Battery 61 Circuit Performance

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: P1B99 Cadillac indicates Hybrid/Electric Vehicle Battery 61 Circuit Performance.
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 820

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
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Code P1B99 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 P1B99 Cadillac - Hybrid/Electric Vehicle Battery 61 Circuit Performance - AutoCodes.com — P1B99 Cadillac Code - Hybrid/Electric Vehicle Battery 61 Circuit Performance

What does this mean?

What are the Possible Causes of the DTC P1B99 Cadillac?

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

How to Fix the DTC P1B99 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 P1B99 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 P1B99 Cadillac Code

1. What does the OBDII code P1B99 mean on a Cadillac?

The P1B99 code indicates an issue with the Hybrid/Electric Vehicle Battery 61 Circuit Performance, meaning the system has detected irregular performance in one of the battery circuits.

2. What are the common symptoms of the P1B99 code?

Symptoms may include the check engine light turning on, reduced hybrid or electric vehicle performance, decreased fuel efficiency, or difficulty maintaining battery charge.

3. What causes the P1B99 code on a Cadillac?

Potential causes include a faulty battery module, poor electrical connections in the battery circuit, damaged wiring, or a malfunctioning battery control module.

4. Can I drive my Cadillac with the P1B99 code active?

It is not recommended to drive with this code active, as it can affect vehicle performance and potentially damage the hybrid/electric battery system.

5. How is the P1B99 code diagnosed?

A technician will typically use a scan tool to read the code, inspect the battery circuit for loose connections or damaged wiring, and test the performance of the battery module and control unit.

6. What repairs are needed to fix the P1B99 code?

Repairs may involve replacing a faulty battery module, repairing or replacing damaged wiring, cleaning and securing connections, or reprogramming the battery control module.

7. How much does it cost to fix a P1B99 code on a Cadillac?

Repair costs vary depending on the exact issue but can range from $200 for minor wiring repairs to over $1,000 if a battery module or control unit needs replacement.

8. What should I do if the P1B99 code keeps coming back after repairs?

If the code persists, have a professional recheck the system for overlooked issues, such as hidden wiring damage or a failing control module.

9. Can a weak 12-volt battery cause the P1B99 code?

While the 12-volt battery generally does not directly cause this code, a weak or failing 12-volt battery can indirectly affect hybrid system performance and should be checked.

10. Is the P1B99 code covered under warranty for Cadillac vehicles?

If your vehicle is still under the hybrid or electric battery warranty, the issue may be covered. Check with your dealership for confirmation.