AutoCodes – Generic – P1B51

P1B51 Code - Hybrid/Electric Vehicle Battery 37 Circuit Low 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: P1B51 indicates Hybrid/Electric Vehicle Battery 37 Circuit Low 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 1,063

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 09, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P1B51 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 P1B51 - Hybrid/Electric Vehicle Battery 37 Circuit Low Voltage - AutoCodes.com — P1B51 Code - Hybrid/Electric Vehicle Battery 37 Circuit Low Voltage

What does this mean?

What are the Possible Causes of the DTC P1B51?

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

How to Fix the DTC P1B51?

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 P1B51 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

P1B51 Buick — Hybrid/Electric Vehicle Battery 37 Circuit Low Voltage
P1B51 Cadillac — Hybrid/Electric Vehicle Battery 37 Circuit Low Voltage
P1B51 Chevrolet — Hybrid/Electric Vehicle Battery 37 Circuit Low Voltage
P1B51 GMC — Hybrid/Electric Vehicle Battery 37 Circuit Low Voltage
P1B51 Saturn — Hybrid/Electric Vehicle Battery 37 Circuit Low 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 P1B51 Code

1. What are the common symptoms of OBDII code P1B51 (Hybrid/Electric Vehicle Battery 37 Circuit Low Voltage)?

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

2. What are the possible causes of OBDII code P1B51?

- The code P1B51 can be triggered by issues such as a faulty hybrid/electric vehicle battery, damaged battery wiring, or a problem with the battery control module.

3. How serious is OBDII code P1B51 (Hybrid/Electric Vehicle Battery 37 Circuit Low Voltage)?

- This code should be addressed promptly as it can impact the performance and efficiency of the vehicle. Ignoring the issue may lead to further damage to the battery system.

4. Can I continue driving with OBDII code P1B51 active?

- It is not recommended to drive with the code active as it may lead to further damage to the vehicle's battery system. It's best to have the issue diagnosed and repaired as soon as possible.

5. How can I diagnose OBDII code P1B51 at home?

- While it's always best to have a professional diagnose the issue, you can start by checking the battery connections, inspecting the wiring for any visible damage, and ensuring the battery is in good condition.

6. What should I do if I encounter OBDII code P1B51?

- If you see this code, it's advisable to have the vehicle inspected by a qualified technician to determine the exact cause of the low voltage issue in the hybrid/electric vehicle battery system.

7. Are there any specific repair tips for addressing OBDII code P1B51?

- Repair tips may include checking and cleaning battery terminals, inspecting battery wiring for damage, testing the battery voltage, and resetting the fault code to see if it reoccurs.

8. How much does it typically cost to repair OBDII code P1B51?

- The cost of repairing this code can vary depending on the exact cause of the issue. It's best to get a diagnostic assessment from a professional to determine the cost of repairs.

9. Can extreme weather conditions trigger OBDII code P1B51?

- Yes, extreme temperatures can potentially affect the performance of hybrid/electric vehicle batteries, leading to issues like low voltage and triggering the P1B51 fault code.

10. How can I prevent OBDII code P1B51 from recurring?

- Regular maintenance of the hybrid/electric vehicle's battery system, including keeping connections clean and secure, can help prevent issues that may trigger the P1B51 fault code.