AutoCodes – Saturn – P1E78 Saturn

P1E78 Saturn Code - Hybrid/Electric Vehicle Battery 77 Circuit

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: P1E78 Saturn indicates Hybrid/Electric Vehicle Battery 77 Circuit.
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 919

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 14, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P1E78 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 P1E78 Saturn - Hybrid/Electric Vehicle Battery 77 Circuit - AutoCodes.com — P1E78 Saturn Code - Hybrid/Electric Vehicle Battery 77 Circuit

What does this mean?

What are the Possible Causes of the DTC P1E78 Saturn?

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

How to Fix the DTC P1E78 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 P1E78 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 P1E78 Saturn Code

1. What does the OBDII code P1E78 mean on a Saturn vehicle?

The P1E78 code indicates an issue with the Hybrid/Electric Vehicle Battery 77 Circuit, which is related to the voltage sensing or communication for the battery control module.

2. What are common symptoms of the P1E78 code in a Saturn?

Symptoms may include the illumination of the check engine light, reduced hybrid or EV performance, limited battery charging or discharging, and potential vehicle hesitation.

3. What causes the P1E78 code to appear?

Common causes include a faulty hybrid battery sensor, damaged wiring or connectors in the Battery 77 Circuit, a failing battery control module, or degraded hybrid battery cells.

4. Can the P1E78 code damage my hybrid or electric vehicle?

If unresolved, the P1E78 code can lead to reduced battery efficiency or performance, potentially causing long-term damage to the hybrid battery system.

5. How is the P1E78 code diagnosed?

A mechanic will use a scan tool to retrieve the code, inspect the battery module and wiring, test the battery sensor circuit, and check for related codes to pinpoint the issue.

6. Can I drive my Saturn with the P1E78 code?

You may be able to drive it, but itâ€™s not recommended as it could lead to reduced performance, further battery damage, or unsafe driving conditions.

7. How can the P1E78 code be fixed?

Repairs may include replacing a faulty hybrid battery sensor, repairing or replacing damaged wiring or connectors, reprogramming or replacing the battery control module, or replacing the hybrid battery if necessary.

8. What tools are needed to fix the P1E78 code?

Youâ€™ll need an OBDII scanner, a multimeter for testing voltage and continuity, and potentially specialized tools for accessing and servicing the hybrid battery system.

9. Is the P1E78 code covered under warranty?

It depends on the vehicleâ€™s warranty and the age of the hybrid battery. Hybrid components often have extended warranties, so check with your dealership.

10. How much does it cost to repair the P1E78 code?

Repair costs vary widely but can range from $200 to $1,500 or more, depending on whether the issue is a minor wiring problem or a major battery replacement.