AutoCodes – Generic – U1846

U1846 Code - Drive Motor Control Module 2 Lost Communication With Hybrid/EV Powertrain Control Module

Quick Answer

The Drive Motor Control Modules and the Hybrid/EV Powertrain Control Module 1 are all internal to the Power Inverter Module. Common causes include Faulty Power Inverter Module, Power Inverter Module harness is open or shorted, Power Inverter 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: U1846 indicates Drive Motor Control Module 2 Lost Communication With Hybrid/EV Powertrain Control Module.
Common causes: Common causes include Faulty Power Inverter Module, Power Inverter Module harness is open or shorted, Power Inverter 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 1,025

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 Jun 08, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code U1846 Description

The Drive Motor Control Modules and the Hybrid/EV Powertrain Control Module 1 are all internal to the Power Inverter Module. The Drive Motor Control Modules communicate only with the Hybrid/EV Powertrain Control Module 1 which sends out diagnostic trouble code information to other devices regarding the Drive Motor Control Modules. All circuits to the Hybrid/EV Powertrain Control Module 1 and Drive Motor Control Modules are also internal to the Power Inverter Module and replaced as a single component.
Communication diagnostics for the serial data, including device power and ground as well as the wakeup circuits for Drive Motor Control Modules and the Hybrid/EV Powertrain Control Module 1 are all diagnosed from external sources only to the Power Inverter Module connector because any circuit fault condition within the Power Inverter Module will cause a complete replacement.
The Diagnostic Trouble Code (DTC) will set when a supervised periodic message that includes the transmitter device availability has not been received.

OBDII Code U1846 - Drive Motor Control Module 2 Lost Communication With Hybrid/EV Powertrain Control Module - AutoCodes.com — U1846 Code - Drive Motor Control Module 2 Lost Communication With Hybrid/EV Powertrain Control Module

What does this mean?

What are the Possible Causes of the DTC U1846?

Faulty Power Inverter Module
Power Inverter Module harness is open or shorted
Power Inverter Module circuit poor electrical connection

How to Fix the DTC U1846?

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 U1846 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 U1846 code?

Need more information on how to fix the U1846 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the U1846 code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

U1846 Buick — Drive Motor Control Module 2 Lost Communication With Hybrid/EV Powertrain Control Module
U1846 Cadillac — Drive Motor Control Module 2 Lost Communication With Hybrid/EV Powertrain Control Module
U1846 Chevrolet — Drive Motor Control Module 2 Lost Communication With Hybrid/EV Powertrain Control Module
U1846 GMC — Drive Motor Control Module 2 Lost Communication With Hybrid/EV Powertrain Control Module

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 U1846 Code

1. What are the common symptoms of OBDII code U1846?

The common symptoms of OBDII code U1846 include issues with the hybrid/EV powertrain control module, drive motor control module 2 communication problems, and potential drivability issues in hybrid or electric vehicles.

2. What are the possible causes of OBDII code U1846?

Possible causes of OBDII code U1846 can include damaged wiring or connectors, a faulty drive motor control module 2, issues with the hybrid/EV powertrain control module, or a communication breakdown between these modules.

3. How can I diagnose OBDII code U1846?

Diagnosing OBDII code U1846 typically involves using a scan tool to retrieve the code, checking for any related codes, inspecting the wiring and connectors for damage, testing the drive motor control module 2 and hybrid/EV powertrain control module, and verifying communication between the modules.

4. What are some repair tips for fixing OBDII code U1846?

Repair tips for fixing OBDII code U1846 may include repairing or replacing damaged wiring or connectors, replacing a faulty drive motor control module 2 or hybrid/EV powertrain control module, ensuring proper communication between the modules, and performing a thorough system reset.

5. Can OBDII code U1846 be cleared/reset without fixing the underlying issue?

While OBDII codes can be cleared/reset using a scan tool, it is not recommended to do so without fixing the underlying issue causing code U1846. Clearing the code without addressing the root cause may lead to recurring problems and potential safety hazards.

6. How serious is OBDII code U1846?

OBDII code U1846, indicating a loss of communication between the drive motor control module 2 and hybrid/EV powertrain control module, should be addressed promptly to prevent potential drivability issues and ensure the proper functioning of the vehicle's hybrid or electric powertrain system.

7. Is it safe to continue driving with OBDII code U1846 present?

It is not recommended to continue driving with OBDII code U1846 present, as it may lead to performance issues and potential safety concerns related to the hybrid or electric powertrain system. It is advisable to have the issue diagnosed and repaired by a qualified technician.

8. How much does it typically cost to repair OBDII code U1846?

The cost of repairing OBDII code U1846 can vary depending on the underlying cause of the issue, the extent of the repair needed, and the labor rates of the repair facility. It is advisable to obtain a diagnosis and repair estimate from a trusted automotive service provider.

9. Can a DIY enthusiast fix OBDII code U1846 at home?

Fixing OBDII code U1846 at home may be challenging for DIY enthusiasts, as it requires specialized diagnostic tools, knowledge of hybrid or electric powertrain systems, and the ability to safely work on vehicle electronics. It is recommended to consult a professional technician for proper diagnosis and repair.

10. How can I prevent OBDII code U1846 from occurring in the future?

To prevent OBDII code U1846 from occurring in the future, it is essential to maintain regular vehicle maintenance, address any warning signs promptly, avoid electrical system modifications unless performed by a qualified professional, and follow the manufacturer's recommended service intervals for hybrid or electric vehicles.