AutoCodes – Toyota – P0B79 Toyota

P0B79 Toyota Code - Hybrid Battery Voltage Sense 'M' Circuit Low

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: P0B79 Toyota indicates Hybrid Battery Voltage Sense 'M' Circuit Low.
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 5,050

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 08, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P0B79 Toyota 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 P0B79 Toyota - Hybrid Battery Voltage Sense 'M' Circuit Low - AutoCodes.com — P0B79 Toyota Code - Hybrid Battery Voltage Sense 'M' Circuit Low

What does this mean?

What are the Possible Causes of the DTC P0B79 Toyota?

Faulty Battery smart unit
Faulty HV battery assembly

How to Fix the DTC P0B79 Toyota?

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 P0B79 Toyota 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 P0B79 Toyota Code

1. What are common symptoms of OBDII code P0B79 in a Toyota related to the Hybrid Battery Voltage Sense 'M' Circuit Low?

- Common symptoms include decreased fuel efficiency, loss of power, and difficulty starting the vehicle.

2. What are the possible causes of OBDII code P0B79 in a Toyota?

- The code P0B79 can be triggered by issues such as a faulty hybrid battery voltage sensor, damaged wiring, or a problem with the hybrid battery itself.

3. How can I diagnose the Hybrid Battery Voltage Sense 'M' Circuit Low issue in my Toyota?

- Diagnosis often involves using an OBDII scanner to retrieve the specific code, checking the hybrid battery voltage sensor, and inspecting the wiring for any signs of damage.

4. Can I continue driving my Toyota with the P0B79 code present?

- It is not recommended to continue driving the vehicle with the P0B79 code present, as it can lead to further damage to the hybrid battery system.

5. Are there any DIY repair tips for fixing the Hybrid Battery Voltage Sense 'M' Circuit Low issue in a Toyota?

- DIY repair tips may include checking and cleaning the battery terminals, inspecting the wiring for any visible damage, and resetting the error code to see if it reoccurs.

6. How much does it typically cost to repair the P0B79 code in a Toyota at a dealership or repair shop?

- The cost of repairing the P0B79 code can vary depending on the exact cause, but it may range from a few hundred dollars to over a thousand dollars, especially if parts need to be replaced.

7. Can a faulty hybrid battery voltage sensor cause other issues in a Toyota besides triggering the P0B79 code?

- Yes, a faulty hybrid battery voltage sensor can cause other issues such as inaccurate battery level readings, improper charging, and overall performance issues.

8. How long does it usually take to repair the Hybrid Battery Voltage Sense 'M' Circuit Low problem in a Toyota?

- The repair time can vary depending on the severity of the issue and the availability of parts, but it typically takes a few hours to a full day to diagnose and fix the problem.

9. Is it possible to prevent the P0B79 code from occurring in my Toyota?

- Regular maintenance of the hybrid battery system, including checking the battery voltage sensor and keeping the wiring in good condition, can help prevent the P0B79 code from occurring.

10. Can I reset the OBDII code P0B79 in my Toyota using a simple battery disconnect method?

- While disconnecting the battery may reset the code temporarily, it is recommended to diagnose and repair the underlying issue causing the P0B79 code for a permanent solution.