AutoCodes – Generic – P1FD9

P1FD9 Code - Hybrid/EV Battery Interface Control Module 5 Voltage Sensor Circuit Low Voltage

Quick Answer

The hybrid battery contains 192 individual cells. Common causes include Faulty Hybrid/EV Battery Interface Control Module, Hybrid/EV Battery Interface Control Module harness is open or shorted, Hybrid/EV Battery Interface Control Module circuit poor electrical connection. 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: P1FD9 indicates Hybrid/EV Battery Interface Control Module 5 Voltage Sensor Circuit Low Voltage.
Common causes: Common causes include Faulty Hybrid/EV Battery Interface Control Module, Hybrid/EV Battery Interface Control Module harness is open or shorted, Hybrid/EV Battery Interface Control Module circuit poor electrical connection.
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 858

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 27, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P1FD9 Description

The hybrid battery contains 192 individual cells. Two cells are welded together in parallel and called a cell group. There are a total of 96 cell groups in the hybrid battery 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 cell groups are joined to form 3 distinct sections. The first 24 battery cell groups make up battery section 1. This section is adjacent to the cowl and contains battery cell groups 73 through 96. The next 28 battery cell groups make up battery section 2. This section is located behind section 1 and contains battery cell groups 45 through 72. The transverse battery section is section number 3 and it contains the remaining 44 battery cell groups 1 through 44. The battery sections also contain two temperature sensors, with one sensor located at each end of the section.
The battery energy control module monitors the voltage of the 96 battery cell groups. The voltage sense lines are attached to each individual cell group, and these sense lines terminate at a connector located on the top surface of the battery section. A voltage sense harness joins this connector to the battery energy control module.
The battery energy control module contains internal interface control modules that monitor specific cell groups.
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 the hybrid powertrain control module 2 through serial data. The hybrid powertrain control module 2 is the host controller for diagnostic trouble code information.

OBDII Code P1FD9 - Hybrid/EV Battery Interface Control Module 5 Voltage Sensor Circuit Low Voltage - AutoCodes.com — P1FD9 Code - Hybrid/EV Battery Interface Control Module 5 Voltage Sensor Circuit Low Voltage

What does this mean?

What are the Possible Causes of the DTC P1FD9?

Faulty Hybrid/EV Battery Interface Control Module
Hybrid/EV Battery Interface Control Module harness is open or shorted
Hybrid/EV Battery Interface Control Module circuit poor electrical connection

How to Fix the DTC P1FD9?

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 P1FD9 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.

Need more information about the P1FD9 code?

Need more information on how to fix the P1FD9 code? Get Access to Factory Service Manuals

Need Help with the Code?

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Information for Specific Makes

P1FD9 Buick — Hybrid/EV Battery Interface Control Module 5 Voltage Sensor Circuit Low Voltage
P1FD9 Cadillac — Hybrid/EV Battery Interface Control Module 5 Voltage Sensor Circuit Low Voltage
P1FD9 Chevrolet — Hybrid/EV Battery Interface Control Module 5 Voltage Sensor Circuit Low Voltage
P1FD9 GMC — Hybrid/EV Battery Interface Control Module 5 Voltage Sensor Circuit Low Voltage
P1FD9 Saturn — Hybrid/EV Battery Interface Control Module 5 Voltage Sensor Circuit Low Voltage

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 P1FD9 Code

What does the OBDII code P1FD9 mean?

The P1FD9 code indicates that the Hybrid/EV Battery Interface Control Module 5 has detected a low voltage in its voltage sensor circuit.

What are the common symptoms of the P1FD9 code?

Symptoms may include an illuminated check engine light, reduced hybrid/EV system performance, decreased fuel efficiency, or limited electric driving range.

What causes the P1FD9 code to appear?

The code can be triggered by a faulty voltage sensor, damaged wiring or connectors in the sensor circuit, a malfunctioning battery interface control module, or issues with the hybrid/EV battery pack itself.

Can you drive with the P1FD9 code?

Driving with this code is not recommended as it may lead to reduced performance or further damage to the hybrid/EV battery system.

How is the P1FD9 code diagnosed?

A technician will use a scan tool to confirm the code, inspect the voltage sensor circuit for damage, test the sensor and related wiring, and evaluate the hybrid/EV battery system for faults.

What repairs can fix the P1FD9 code?

Repairs may include replacing the faulty voltage sensor, repairing or replacing damaged wiring or connectors, or in some cases, replacing the hybrid/EV battery interface control module.

Can a weak hybrid/EV battery cause the P1FD9 code?

Yes, a weak or failing hybrid/EV battery can potentially cause voltage irregularities that trigger the P1FD9 code.

Is the P1FD9 code specific to certain vehicles?

Yes, this code is typically found in hybrid and electric vehicles, and its exact meaning and diagnostic steps may vary by manufacturer.

How much does it cost to fix the P1FD9 code?

The repair cost depends on the exact cause, ranging from $100 for wiring repairs to over $1,000 if the battery interface control module needs replacement.

Can the P1FD9 code clear itself?

The code is unlikely to clear itself, as it indicates a persistent issue. Repairs are usually required to resolve the underlying problem and clear the code.