AutoCodes – Saturn – P1B78 Saturn

P1B78 Saturn Code - Hybrid/Electric Vehicle Battery 50 Circuit Performance

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: P1B78 Saturn indicates Hybrid/Electric Vehicle Battery 50 Circuit Performance.
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 909

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 P1B78 Saturn 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 P1B78 Saturn - Hybrid/Electric Vehicle Battery 50 Circuit Performance - AutoCodes.com — P1B78 Saturn Code - Hybrid/Electric Vehicle Battery 50 Circuit Performance

What does this mean?

What are the Possible Causes of the DTC P1B78 Saturn?

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

How to Fix the DTC P1B78 Saturn?

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 P1B78 Saturn 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 P1B78 Saturn Code

1. What does the OBDII code P1B78 mean for a Saturn vehicle?

It indicates a performance issue in the Hybrid/Electric Vehicle Battery 50 Circuit, which relates to the electrical or voltage performance of the hybrid battery system.

2. What are common symptoms of the P1B78 code in a Saturn?

Symptoms may include a warning light on the dashboard, reduced fuel efficiency, limited electric motor performance, or the vehicle operating in reduced power mode.

3. What causes the P1B78 code to appear?

Common causes include a malfunctioning hybrid battery cell, damaged wiring or connectors, a failed battery control module, or corrosion in the electrical circuits.

4. Can I drive my Saturn with the P1B78 code active?

It is not recommended, as driving with this code can lead to further damage to the hybrid battery system or reduced vehicle performance.

5. How is the P1B78 code diagnosed?

A technician will use a scan tool to read the code, inspect the hybrid battery and related circuits, check for damaged wiring, and test the battery control module.

6. What repairs can fix the P1B78 code on a Saturn?

Repairs may include replacing a faulty hybrid battery cell, repairing damaged wiring or connectors, or replacing the hybrid battery control module.

7. How much does it cost to fix the P1B78 code?

Costs can vary widely depending on whether the issue is with a single wire or requires replacement of the hybrid battery, ranging from a few hundred to several thousand dollars.

8. Can a weak 12-volt battery trigger the P1B78 code?

While unlikely, a weak or failing 12-volt battery can sometimes contribute to hybrid system errors and should be tested during diagnosis.

9. What maintenance can prevent the P1B78 code from occurring?

Regularly inspecting the hybrid system for corrosion, ensuring all connections are secure, and promptly addressing warning lights can help prevent this code.

10. Do I need to replace the entire hybrid battery if I get the P1B78 code?

Not always. Sometimes the issue is isolated to a single cell or circuit, which can be repaired without replacing the whole battery pack.