AutoCodes – GMC – P1B78 GMC

P1B78 GMC 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 GMC 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.

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Code Popularity 870

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

What does this mean?

What are the Possible Causes of the DTC P1B78 GMC?

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

How to Fix the DTC P1B78 GMC?

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 GMC 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 P1B78 GMC Code

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

- Common symptoms include reduced battery performance, decreased fuel efficiency, and potential issues with the vehicle's hybrid system.

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

- The code P1B78 typically indicates a problem with the Hybrid/Electric Vehicle Battery 50 Circuit, which can be caused by issues with the battery pack, wiring, connectors, or control modules.

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

- Diagnosing OBDII code P1B78 requires using a professional OBDII scanner to read the code, followed by a thorough inspection of the hybrid/electric battery system components and related wiring.

4. Can I still drive my GMC hybrid/electric vehicle with OBDII code P1B78 present?

- It is not recommended to drive the vehicle with code P1B78 present, as it can lead to further damage to the hybrid/electric system and potentially unsafe driving conditions.

5. What are some repair tips for fixing OBDII code P1B78 in a GMC hybrid/electric vehicle?

- Repair tips include checking and repairing any damaged wiring, replacing faulty battery cells or modules, ensuring proper connections, and resetting the OBDII code after repairs are completed.

6. How much does it typically cost to repair OBDII code P1B78 in a GMC hybrid/electric vehicle?

- The cost of repairing OBDII code P1B78 can vary depending on the extent of the issue, but it may involve expenses for parts replacement, labor, and diagnostic services.

7. Can OBDII code P1B78 be a recurring issue in a GMC hybrid/electric vehicle?

- If the root cause of the code P1B78 is not properly addressed during repairs, it can potentially reoccur, emphasizing the importance of thorough diagnosis and repair.

8. Is it safe to attempt DIY repairs for OBDII code P1B78 in a GMC hybrid/electric vehicle?

- DIY repairs for code P1B78 may be challenging due to the complexity of the hybrid/electric system. It is recommended to seek professional help to ensure proper diagnosis and repair.

9. How long does it typically take to fix OBDII code P1B78 in a GMC hybrid/electric vehicle?

- The repair time for OBDII code P1B78 can vary depending on the specific issue, but it may take several hours to a full day for diagnosis and repairs to be completed.

10. Are there any recalls or technical service bulletins related to OBDII code P1B78 in GMC hybrid/electric vehicles?

- It is advisable to check with GMC dealerships or online resources for any recalls or technical service bulletins related to OBDII code P1B78 to stay informed about potential updates or solutions provided by the manufacturer.