AutoCodes – GMC – P1B74 GMC

P1B74 GMC Code - Hybrid/Electric Vehicle Battery 48 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: P1B74 GMC indicates Hybrid/Electric Vehicle Battery 48 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 803

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 P1B74 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 P1B74 GMC - Hybrid/Electric Vehicle Battery 48 Circuit High Voltage - AutoCodes.com — P1B74 GMC Code - Hybrid/Electric Vehicle Battery 48 Circuit High Voltage

What does this mean?

What are the Possible Causes of the DTC P1B74 GMC?

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

How to Fix the DTC P1B74 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 P1B74 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 P1B74 GMC Code

What does the OBDII code P1B74 mean for a GMC vehicle?

P1B74 indicates a problem with the high voltage circuit of the hybrid or electric vehicle battery, specifically that the voltage is too high.

What are common symptoms of the P1B74 code?

Common symptoms include warning lights on the dashboard, reduced power or performance, and possible erratic behavior of the hybrid system.

What could cause the P1B74 code to trigger?

Causes can include a faulty battery, damaged wiring or connectors in the high voltage circuit, or a malfunctioning battery management system.

Is it safe to drive a vehicle with the P1B74 code?

It's generally not safe to drive, as high voltage issues can lead to battery failure or other electrical problems that could compromise vehicle safety.

How can I diagnose the P1B74 code?

Start by using an OBDII scanner to confirm the code, then inspect the battery, wiring, and connectors for any visible damage or wear. A more in-depth diagnostic may require specialized tools.

What repairs are typically needed for the P1B74 code?

Repairs may involve replacing the hybrid battery, repairing damaged wiring, or updating the battery management system software.

Can I clear the P1B74 code after repairs?

Yes, after addressing the underlying issue, you can clear the code with an OBDII scanner. However, ensure the problem is resolved first to prevent the code from returning.

How often should I have my hybrid/electric vehicleâ€™s battery checked?

It's advisable to have the battery and its components checked during regular maintenance, or sooner if you notice symptoms related to the battery performance.

Will resetting the check engine light fix the P1B74 code?

Resetting the check engine light will not fix the underlying issue that caused the P1B74 code. The root problem needs to be resolved for the code not to reappear.