AutoCodes – Generic – P0B49

P0B49 Code - Hybrid Battery Voltage Sense 'C' Circuit Intermittent/Erratic

Quick Answer

The HV battery uses nickel metal-hydride batteries and does not require external charging. Common causes include Faulty Battery smart unit, Faulty HV battery assembly. 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: P0B49 indicates Hybrid Battery Voltage Sense 'C' Circuit Intermittent/Erratic.
Common causes: Common causes include Faulty Battery smart unit, Faulty HV battery assembly.
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 2,033

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 07, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P0B49 Description

The HV battery uses nickel metal-hydride batteries and does not require external charging. The power management control ECU controls the SOC (state of charge) of the HV battery at a constant level during driving. The HV battery is composed of 28 modules, and each module consists of eight 1.2 V cells in series. The battery smart unit monitors battery block voltage at 14 locations. Each battery block is composed of 2 modules in a set. The battery smart unit, which monitors the voltage of the battery blocks, determines that malfunction has occurred if a voltage difference between the battery blocks exceeds the standard. When the malfunction detection condition is satisfied, the power management control ECU (HV CPU) will illuminates the Malfunction Indicator Lamp (MIL) and set a Diagnostic Trouble Code (DTC).

OBDII Code P0B49 - Hybrid Battery Voltage Sense 'C' Circuit Intermittent/Erratic - AutoCodes.com — P0B49 Code - Hybrid Battery Voltage Sense 'C' Circuit Intermittent/Erratic

What does this mean?

What are the Possible Causes of the DTC P0B49?

Faulty Battery smart unit
Faulty HV battery assembly

How to Fix the DTC P0B49?

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 P0B49 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 P0B49 Code

What does the OBDII code P0B49 mean?

The P0B49 code indicates an intermittent or erratic voltage reading in the Hybrid Battery Voltage Sense 'C' Circuit, which monitors the voltage of a specific section of the hybrid battery pack.

What are the common symptoms of the P0B49 code?

Symptoms may include an illuminated check engine light, reduced fuel efficiency, limited hybrid system performance, and, in some cases, the vehicle entering a fail-safe or limp mode.

What causes the P0B49 code to appear?

Common causes include damaged or corroded wiring or connectors in the voltage sense circuit, a faulty hybrid battery voltage sensor, or an issue with the hybrid control module.

Can I still drive my car with the P0B49 code?

While it may be possible to drive the car, doing so is not recommended as it could lead to further damage to the hybrid system or battery pack.

How is the P0B49 code diagnosed?

A mechanic will typically use a scan tool to read freeze frame data, inspect the wiring and connectors in the voltage sense circuit, and test the hybrid battery voltage sensor for proper functionality.

What repairs can fix the P0B49 code?

Repairs may include replacing damaged wiring or connectors, replacing the hybrid battery voltage sensor, or, in rare cases, repairing or replacing the hybrid battery pack or control module.

How much does it cost to fix the P0B49 code?

Repair costs can vary widely but typically range from $100 to $500 for wiring or sensor replacements. More extensive repairs, like replacing the hybrid battery pack, can cost thousands of dollars.

Can a low 12-volt auxiliary battery cause the P0B49 code?

A low or failing 12-volt auxiliary battery is unlikely to directly cause this code, but it can lead to erratic electrical behavior that might trigger hybrid system issues.

How can I prevent the P0B49 code from recurring?

Regular maintenance, including checking and cleaning hybrid system wiring and ensuring proper battery health, can help prevent this code from recurring.

Does the P0B49 code mean my hybrid battery is failing?

Not necessarily. While the code involves the hybrid battery system, it is often related to a sensor or wiring issue rather than complete battery failure.