AutoCodes – GMC – P1B77 GMC

P1B77 GMC Code - Hybrid/Electric Vehicle Battery 49 Circuit High 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: P1B77 GMC indicates Hybrid/Electric Vehicle Battery 49 Circuit High 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 1,044

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 P1B77 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 P1B77 GMC - Hybrid/Electric Vehicle Battery 49 Circuit High Voltage - AutoCodes.com — P1B77 GMC Code - Hybrid/Electric Vehicle Battery 49 Circuit High Voltage

What does this mean?

What are the Possible Causes of the DTC P1B77 GMC?

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

How to Fix the DTC P1B77 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 P1B77 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 P1B77 GMC Code

1. What are the common symptoms of OBDII code P1B77 GMC (Hybrid/Electric Vehicle Battery 49 Circuit High Voltage)?

- Common symptoms include reduced hybrid system performance, illuminated warning lights on the dashboard, and potential issues with the high voltage battery system.

2. What can cause the OBDII code P1B77 GMC to trigger?

- This code is typically triggered by a malfunction in the Hybrid/Electric Vehicle Battery 49 Circuit, indicating a high voltage issue within the battery system.

3. How serious is the OBDII code P1B77 GMC?

- This code should be addressed promptly as it pertains to the high voltage system in hybrid/electric vehicles. Ignoring it could lead to further damage and potential safety hazards.

4. How can I diagnose the cause of OBDII code P1B77 GMC?

- Proper diagnosis requires specialized equipment and knowledge of hybrid/electric vehicle systems. It is recommended to seek assistance from a qualified technician or dealership.

5. Can I continue driving my vehicle with the OBDII code P1B77 GMC present?

- It is not recommended to continue driving the vehicle with this code active, as it could lead to further damage to the high voltage battery system.

6. What are some possible repair options for OBDII code P1B77 GMC?

- Repair options may include inspecting and repairing damaged wiring, replacing faulty components within the battery system, or recalibrating the high voltage system.

7. How much does it typically cost to repair OBDII code P1B77 GMC?

- Repair costs can vary depending on the extent of the issue and the specific repairs needed. It is advisable to obtain a professional diagnosis to determine the cost accurately.

8. Can I reset the OBDII code P1B77 GMC on my own?

- While you may be able to clear the code using an OBDII scanner, it is important to address the underlying issue causing the code to prevent it from recurring.

9. Is the OBDII code P1B77 GMC specific to GMC vehicles only?

- This code is specific to GMC hybrid/electric vehicles, indicating a high voltage issue within the battery system of these particular vehicles.

10. How can I prevent OBDII code P1B77 GMC from occurring in the future?

- Regular maintenance and inspections of the high voltage battery system in your hybrid/electric vehicle can help prevent issues that may trigger this code.