AutoCodes – GMC – U1803 2015 GMC Sierra

U1803 2015 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 2015 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 202

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 2015 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 2015 GMC Sierra - Lost Communication with Hybrid/EV Powertrain Control Module 2 - AutoCodes.com — U1803 2015 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 2015 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 2015 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 2015 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 2015 GMC Sierra code?

Need more information on how to fix the U1803 2015 GMC Sierra code? Get Access to Factory Service Manuals

Need Help with the Code?

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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 2015 GMC Sierra Code

1. What are the common symptoms of OBDII code U1803 in a 2015 GMC Sierra?

- Common symptoms include the check engine light coming on, loss of communication with the hybrid/EV powertrain control module 2, and potential drivability issues.

2. What can cause the OBDII code U1803 in a 2015 GMC Sierra?

- The U1803 code is typically triggered by a communication fault between the vehicle's onboard computer systems and the hybrid/EV powertrain control module 2.

3. How serious is the U1803 code in a 2015 GMC Sierra?

- The U1803 code should be addressed promptly as it can affect the proper functioning of the hybrid/EV powertrain system in the vehicle.

4. Can the U1803 code in a 2015 GMC Sierra be easily reset?

- While the code can be cleared with an OBDII scanner, it is important to diagnose and address the underlying communication issue to prevent the code from reoccurring.

5. What are some possible repair tips for resolving the U1803 code in a 2015 GMC Sierra?

- Repair tips may include checking and repairing any damaged wiring or connectors related to the communication system, ensuring proper ground connections, and inspecting the hybrid/EV powertrain control module 2 for faults.

6. Is it safe to continue driving a 2015 GMC Sierra with the U1803 code?

- It is not recommended to drive the vehicle with the U1803 code present, as it can lead to further issues with the hybrid/EV powertrain system and potentially affect vehicle performance.

7. Can a DIY enthusiast diagnose and fix the U1803 code in a 2015 GMC Sierra?

- While some basic troubleshooting steps can be taken, diagnosing and repairing the U1803 code may require specialized tools and knowledge, making it advisable to seek professional help.

8. How much does it typically cost to repair the U1803 code in a 2015 GMC Sierra?

- The cost of repairing the U1803 code can vary depending on the underlying cause, parts needed for replacement, and labor costs. It is best to consult a mechanic for an accurate estimate.

9. Will the U1803 code in a 2015 GMC Sierra affect fuel efficiency?

- The U1803 code can impact the hybrid/EV powertrain system, potentially leading to decreased fuel efficiency if not addressed promptly.

10. How can preventive maintenance help avoid the U1803 code in a 2015 GMC Sierra?

- Regularly servicing and inspecting the vehicle's electrical and communication systems can help prevent issues like the U1803 code from occurring by catching potential faults early.