AutoCodes – GMC – U1803 2016 GMC Sierra

U1803 2016 GMC Sierra Code - Lost Communication with Hybrid/EV Powertrain Control Module 2

Quick Answer

The serial data circuit is the means by which the devices in the vehicle communicate with each other. Common causes include Faulty Hybrid/EV Powertrain Control Module 2, Hybrid/EV Powertrain Control Module 2 harness is open or shorted, Hybrid/EV Powertrain Control Module 2 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: U1803 2016 GMC Sierra indicates Lost Communication with Hybrid/EV Powertrain Control Module 2.
Common causes: Common causes include Faulty Hybrid/EV Powertrain Control Module 2, Hybrid/EV Powertrain Control Module 2 harness is open or shorted, Hybrid/EV Powertrain Control Module 2 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 175

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 Jul 21, 2023

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code U1803 2016 GMC Sierra Description

The serial data circuit is the means by which the devices in the vehicle communicate with each other. Once the scan tool is connected to the serial data circuit through the Data Link Connector (DLC), the scan tool can be used to monitor each device for diagnostic purposes and to check for Diagnostic Trouble Codes (DTC). When the vehicle is ON, each device communicating on the serial data circuit sends a state of health message to ensure that the device is operating properly. When a device stops communicating on the serial data circuit, for example, if the device loses power or ground, the state of health message it normally sends on the serial data circuit disappears. Other devices on the serial data circuit, which expect to receive that state of health message, detect its absence; those devices in turn set a DTC associated with the loss of state of health of the non-communicating device. A loss of serial data communications DTC does not represent a failure of the devices that contain the stored DTC.

OBDII Code U1803 2016 GMC Sierra - Lost Communication with Hybrid/EV Powertrain Control Module 2 - AutoCodes.com — U1803 2016 GMC Sierra Code - Lost Communication with Hybrid/EV Powertrain Control Module 2

What does this mean?

What are the Possible Causes of the DTC U1803 2016 GMC Sierra?

Faulty Hybrid/EV Powertrain Control Module 2
Hybrid/EV Powertrain Control Module 2 harness is open or shorted
Hybrid/EV Powertrain Control Module 2 circuit poor electrical connection

How to Fix the DTC U1803 2016 GMC Sierra?

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 U1803 2016 GMC Sierra 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 U1803 2016 GMC Sierra code?

Need more information on how to fix the U1803 2016 GMC Sierra code? Get Access to Factory Service Manuals

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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 U1803 2016 GMC Sierra Code

1. What does the OBDII code U1803 mean on a 2016 GMC Sierra?

The U1803 code indicates a lost communication with Hybrid/EV Powertrain Control Module 2, suggesting a network communication issue in the vehicle's data bus system.

2. What are the symptoms of code U1803 on a 2016 GMC Sierra?

Symptoms may include warning lights on the dashboard, reduced engine performance, issues with hybrid/EV functionality (if equipped), or failure of certain systems to operate properly.

3. What causes the U1803 code to appear on a 2016 GMC Sierra?

Common causes include faulty wiring or connectors in the communication network, a malfunctioning Hybrid/EV Powertrain Control Module 2, poor grounding, or a failing battery or alternator.

4. Can a weak battery cause the U1803 code in a 2016 GMC Sierra?

Yes, a weak battery or charging system issue can disrupt communication between modules and trigger the U1803 code.

5. How do I diagnose the U1803 code on a 2016 GMC Sierra?

Start by inspecting wiring and connectors for damage or corrosion, testing the battery and alternator, and verifying communication with the Hybrid/EV Powertrain Control Module 2 using a scan tool.

6. Can I drive my 2016 GMC Sierra with the U1803 code?

Driving with the U1803 code is not recommended, as it may indicate issues with critical systems, potentially leading to reduced performance or safety concerns.

7. How do you fix the U1803 code on a 2016 GMC Sierra?

Repairs may involve replacing damaged wiring or connectors, resetting the control module, updating software, or replacing the Hybrid/EV Powertrain Control Module 2 if it's defective.

8. Is the U1803 code specific to hybrid or EV-equipped 2016 GMC Sierra models?

Yes, the U1803 code is specific to hybrid or EV-equipped models because it relates to communication with the Hybrid/EV Powertrain Control Module 2.

9. How much does it cost to repair the U1803 code on a 2016 GMC Sierra?

Repair costs can vary but typically range from $100 to $1,000, depending on whether the issue involves minor wiring repairs or replacement of the control module.

10. Can a software update fix the U1803 code on a 2016 GMC Sierra?

In some cases, a software update for the vehicleâ€™s control modules may resolve communication issues and clear the U1803 code.