AutoCodes – Generic – P1B74

P1B74 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 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 14,636

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

What does this mean?

What are the Possible Causes of the DTC P1B74?

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

How to Fix the DTC P1B74?

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 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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Need Help with the Code?

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Information for Specific Makes

P1B74 Buick — Hybrid/Electric Vehicle Battery 48 Circuit High Voltage
P1B74 Cadillac — Hybrid/Electric Vehicle Battery 48 Circuit High Voltage
P1B74 Chevrolet — Hybrid/Electric Vehicle Battery 48 Circuit High Voltage
P1B74 GMC — Hybrid/Electric Vehicle Battery 48 Circuit High Voltage
P1B74 Saturn — Hybrid/Electric Vehicle Battery 48 Circuit High Voltage

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 Code

1. What are common symptoms of OBDII code P1B74 Hybrid/Electric Vehicle Battery 48 Circuit High Voltage?

- Common symptoms include the hybrid or electric vehicle not starting, reduced power, and the hybrid system warning light illuminated on the dashboard.

2. What are the possible causes of OBDII code P1B74 Hybrid/Electric Vehicle Battery 48 Circuit High Voltage?

- Possible causes may include a faulty high voltage battery, damaged wiring in the battery circuit, or issues with the battery management system.

3. How can I diagnose OBDII code P1B74 Hybrid/Electric Vehicle Battery 48 Circuit High Voltage?

- Diagnosis typically involves using a professional OBDII scanner to read the code, inspecting the high voltage battery connections, and testing the battery voltage levels.

4. Can I drive my vehicle with OBDII code P1B74 Hybrid/Electric Vehicle Battery 48 Circuit High Voltage?

- It is not advisable to drive the vehicle with this code present, as it can lead to further damage to the high voltage system and potentially unsafe driving conditions.

5. How can I repair OBDII code P1B74 Hybrid/Electric Vehicle Battery 48 Circuit High Voltage?

- Repair may involve replacing the high voltage battery, repairing or replacing damaged wiring, or resetting the battery management system using specialized tools.

6. Is it safe to attempt repairs on the high voltage system associated with OBDII code P1B74?

- Due to the high voltage nature of the system, it is recommended to have repairs and diagnostics performed by a qualified technician familiar with hybrid/electric vehicle systems.

7. How can I prevent OBDII code P1B74 Hybrid/Electric Vehicle Battery 48 Circuit High Voltage from occurring?

- Regular maintenance of the high voltage battery system, including inspections and testing, can help prevent issues that lead to this fault code.

8. Can a low 12V auxiliary battery cause OBDII code P1B74 Hybrid/Electric Vehicle Battery 48 Circuit High Voltage?

- Yes, a weak or faulty 12V auxiliary battery can sometimes trigger this code due to inadequate power supply to the high voltage system.

9. Will resetting the fault code make OBDII code P1B74 Hybrid/Electric Vehicle Battery 48 Circuit High Voltage go away permanently?

- Resetting the fault code may temporarily clear the warning, but if the underlying issue is not addressed, the code is likely to reappear.

10. Are there any safety precautions I should take when dealing with OBDII code P1B74 Hybrid/Electric Vehicle Battery 48 Circuit High Voltage?

- Yes, always follow proper safety procedures when working on high voltage systems, including wearing insulated gloves, avoiding contact with exposed wires, and disconnecting the battery before starting any repairs.