AutoCodes – Cadillac – P1B73 Cadillac

P1B73 Cadillac Code - Hybrid/Electric Vehicle Battery 48 Circuit Low Voltage

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: P1B73 Cadillac indicates Hybrid/Electric Vehicle Battery 48 Circuit Low Voltage.
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 819

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 P1B73 Cadillac 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 P1B73 Cadillac - Hybrid/Electric Vehicle Battery 48 Circuit Low Voltage - AutoCodes.com — P1B73 Cadillac Code - Hybrid/Electric Vehicle Battery 48 Circuit Low Voltage

What does this mean?

What are the Possible Causes of the DTC P1B73 Cadillac?

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

How to Fix the DTC P1B73 Cadillac?

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 P1B73 Cadillac 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 P1B73 Cadillac Code

1. What does the OBDII code P1B73 mean on a Cadillac?

P1B73 indicates a low voltage issue in the Hybrid/Electric Vehicle Battery 48 Volt circuit, typically related to the battery or electrical connections.

2. What are the common symptoms of a P1B73 code?

Symptoms may include a check engine light, reduced power mode, decreased fuel efficiency, or limited hybrid/electric system functionality.

3. What causes the P1B73 code to appear?

Possible causes include a malfunctioning hybrid battery, faulty wiring or connectors in the 48-volt circuit, or a failed hybrid battery control module.

4. Can I drive my Cadillac with a P1B73 code?

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

5. How is the P1B73 code diagnosed?

A technician will use a scan tool to verify the code, inspect the 48-volt circuit wiring and connections, and test the hybrid battery and related components.

6. Can a dead 12-volt battery cause a P1B73 code?

While the 12-volt battery is separate from the hybrid system, issues with it can sometimes trigger related electrical faults or disrupt diagnostics.

7. How much does it cost to fix a P1B73 code?

Repair costs vary, but they can range from $200 for wiring repairs to over $1,000 if the hybrid battery or control module needs replacement.

8. Can a software update fix a P1B73 code?

In some cases, a software update for the hybrid system control module may resolve the issue, but only after verifying no hardware problems exist.

9. What tools are needed to fix a P1B73 code?

Proper diagnosis and repair require an OBDII scan tool capable of reading hybrid system codes, a multimeter, and access to Cadillac-specific wiring diagrams.

10. How can I prevent the P1B73 code from returning?

Regular maintenance of the hybrid battery system, ensuring clean and secure electrical connections, and addressing issues promptly can help prevent this code from recurring.