AutoCodes – Cadillac – P1BC9 Cadillac

P1BC9 Cadillac Code - Hybrid/Electric Vehicle Battery 77 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: P1BC9 Cadillac indicates Hybrid/Electric Vehicle Battery 77 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 736

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 P1BC9 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 P1BC9 Cadillac - Hybrid/Electric Vehicle Battery 77 Circuit Performance - AutoCodes.com — P1BC9 Cadillac Code - Hybrid/Electric Vehicle Battery 77 Circuit Performance

What does this mean?

What are the Possible Causes of the DTC P1BC9 Cadillac?

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

How to Fix the DTC P1BC9 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 P1BC9 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 P1BC9 Cadillac Code

1. What does the OBDII code P1BC9 mean on a Cadillac?

P1BC9 indicates an issue with the Hybrid/Electric Vehicle Battery 77 Circuit Performance, typically signaling a problem with the battery pack's voltage sensing or communication.

2. What are the common symptoms of a P1BC9 code?

Symptoms can include the check engine light turning on, reduced fuel efficiency, limited power mode activation, or issues with the hybrid/electric battery system.

3. What causes the P1BC9 code to appear?

Common causes include a faulty battery voltage sensor, wiring or connector issues, damaged battery modules, or a malfunction in the battery control module.

4. Can I continue driving with a P1BC9 code?

It's not recommended to drive for long periods with this code as it can lead to reduced performance or further damage to the hybrid/electric system.

5. How is the P1BC9 code diagnosed?

A technician will use a diagnostic scan tool to check for additional codes, inspect the wiring and connectors, and test the battery modules and voltage sensor for faults.

6. How much does it cost to fix a P1BC9 code?

Repair costs vary depending on the issue but may range from $200 for simple wiring repairs to $3,000 or more if the battery pack needs replacement.

7. Can a P1BC9 code be fixed by resetting the system?

Resetting the system might clear the code temporarily, but the underlying issue must be addressed to prevent the code from returning.

8. Is the P1BC9 code covered under warranty?

Hybrid battery components are often covered under extended warranties, but coverage depends on the vehicle's age and mileage. Check with your dealer.

9. What tools are needed to troubleshoot the P1BC9 code?

You'll need an OBDII scanner capable of reading hybrid-specific codes, a multimeter to test wiring, and possibly manufacturer-specific diagnostic tools.

10. Can a weak 12V battery cause the P1BC9 code?

While unlikely, a weak 12V battery can sometimes cause communication errors, so itâ€™s worth checking its condition as part of the diagnosis.