AutoCodes – Cadillac – P1B78 Cadillac

P1B78 Cadillac Code - Hybrid/Electric Vehicle Battery 50 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: P1B78 Cadillac indicates Hybrid/Electric Vehicle Battery 50 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.

Save to My Repairs My Repairs

AI answers can be wrong. Verify repairs with testing. Open full chat

Code Popularity 882

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
Add Comment

💬 Need more help? Ask Coddy for instant answers — it's free!

Code P1B78 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 P1B78 Cadillac - Hybrid/Electric Vehicle Battery 50 Circuit Performance - AutoCodes.com — P1B78 Cadillac Code - Hybrid/Electric Vehicle Battery 50 Circuit Performance

What does this mean?

What are the Possible Causes of the DTC P1B78 Cadillac?

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

How to Fix the DTC P1B78 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 P1B78 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.

Need more information about the P1B78 Cadillac code?

Need more information on how to fix the P1B78 Cadillac code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P1B78 Cadillac code diagnosed by a professional: Find a repair shop in your area

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 P1B78 Cadillac Code

1. What are the common symptoms of OBDII code P1B78 in a Cadillac hybrid/electric vehicle?

- Common symptoms include reduced battery performance, poor fuel efficiency, illuminated warning lights on the dashboard, and potential engine stalling.

2. What are the possible causes of OBDII code P1B78 in a Cadillac hybrid/electric vehicle?

- The code P1B78 typically indicates issues with the hybrid/electric vehicle battery 50 circuit, which could be caused by wiring faults, damaged battery cells, software glitches, or issues with the battery management system.

3. How can I diagnose the OBDII code P1B78 in my Cadillac hybrid/electric vehicle?

- Diagnosing code P1B78 requires using an OBDII scanner to read the code and then performing a thorough inspection of the hybrid/electric vehicle battery system, including checking the wiring, battery connections, and overall battery health.

4. Can I continue driving my Cadillac with OBDII code P1B78 present?

- It is not recommended to continue driving the vehicle with code P1B78 present, as it can lead to further damage to the hybrid/electric vehicle battery system and potentially compromise vehicle safety and performance.

5. How can I repair OBDII code P1B78 in my Cadillac hybrid/electric vehicle?

- Repairing code P1B78 typically involves addressing the underlying issue with the hybrid/electric vehicle battery 50 circuit, which may require repairing or replacing faulty wiring, addressing battery cell issues, updating software, or seeking professional help from a certified technician.

6. Is it safe to reset the OBDII code P1B78 in my Cadillac without fixing the underlying issue?

- Resetting the code without addressing the underlying problem may temporarily turn off the warning light, but the issue will likely resurface, potentially leading to more severe problems with the hybrid/electric vehicle battery system.

7. How much does it cost to fix OBDII code P1B78 in a Cadillac hybrid/electric vehicle?

- The cost of fixing code P1B78 can vary depending on the underlying issue, but it may range from a few hundred to a few thousand dollars, especially if battery cell replacement or complex wiring repairs are needed.

8. Can code P1B78 in a Cadillac hybrid/electric vehicle be prevented?

- While some causes of code P1B78 may be preventable through regular maintenance and battery system checks, certain issues like battery cell degradation may be unavoidable over time in hybrid/electric vehicles.

9. Are there any DIY repair tips for addressing OBDII code P1B78 in a Cadillac?

- DIY repair tips for code P1B78 may include checking and tightening battery connections, inspecting wiring for visible damage, and ensuring proper battery cooling and maintenance practices are followed to help prevent potential issues.

10. Will fixing OBDII code P1B78 improve my Cadillac's overall performance and fuel efficiency?

- Yes, addressing and fixing code P1B78 in a Cadillac hybrid/electric vehicle can help restore battery performance, improve fuel efficiency, and ensure the vehicle operates optimally without any underlying issues affecting its performance.