AutoCodes – Buick – P1E85 Buick

P1E85 Buick Code - Hybrid/Electric Vehicle Battery 90 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: P1E85 Buick indicates Hybrid/Electric Vehicle Battery 90 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 698

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 Apr 24, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P1E85 Buick 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 P1E85 Buick - Hybrid/Electric Vehicle Battery 90 Circuit - AutoCodes.com — P1E85 Buick Code - Hybrid/Electric Vehicle Battery 90 Circuit

What does this mean?

What are the Possible Causes of the DTC P1E85 Buick?

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

How to Fix the DTC P1E85 Buick?

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 P1E85 Buick 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 P1E85 Buick Code

1. What does OBDII code P1E85 mean for a Buick?

Code P1E85 indicates an issue with the Hybrid/Electric Vehicle Battery 90 Circuit, typically related to the high-voltage battery system in hybrid or electric models.

2. What are the common symptoms of code P1E85 on a Buick?

Symptoms may include an illuminated check engine light, reduced hybrid system performance, limited electric-only mode, or difficulty starting the vehicle.

3. What causes OBDII code P1E85 to appear?

Common causes include wiring harness issues, faulty battery control modules, poor electrical connections, or a malfunctioning hybrid battery cell.

4. Can I drive my Buick with a P1E85 code?

Driving with this code is not recommended, as it can lead to further damage to the hybrid system or leave the vehicle inoperable.

5. How is the P1E85 code diagnosed?

A technician will use a scan tool to read trouble codes, inspect the battery control module, check wiring and connections, and test the high-voltage battery circuit for faults.

6. How do I fix a P1E85 code on my Buick?

Repairs may involve replacing or repairing damaged wiring, cleaning or securing electrical connections, reprogramming the battery control module, or replacing faulty battery components.

7. What tools are needed to diagnose a P1E85 code?

A professional-grade OBDII scanner, multimeter, and possibly a thermal camera for checking battery temperature inconsistencies are typically required.

8. How much does it cost to repair a P1E85 code on a Buick?

Costs can vary widely, ranging from $150 for minor wiring repairs to over $2,000 if the hybrid battery or control module needs replacement.

9. Can a dead 12-volt battery cause a P1E85 code?

While unlikely, a weak or discharged 12-volt battery can sometimes cause hybrid system errors. Always check the 12-volt battery's health before deeper diagnostics.

10. Is the P1E85 code covered under warranty?

It may be covered under the hybrid or battery warranty, depending on your vehicle's age, mileage, and warranty terms. Check with your dealership for specifics.