AutoCodes – GMC – U1803 2014 GMC Sierra

U1803 2014 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 2014 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 216

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 2014 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 2014 GMC Sierra - Lost Communication with Hybrid/EV Powertrain Control Module 2 - AutoCodes.com — U1803 2014 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 2014 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 2014 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 2014 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 2014 GMC Sierra code?

Need more information on how to fix the U1803 2014 GMC Sierra code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the U1803 2014 GMC Sierra code diagnosed by a professional: Find a repair shop in your area

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 2014 GMC Sierra Code

1. What are the common symptoms of OBDII code U1803 in a 2014 GMC Sierra?

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

2. What can cause the U1803 code in a 2014 GMC Sierra?

- The U1803 code is typically triggered when there is a communication fault between the onboard diagnostics system and the hybrid/EV powertrain control module 2.

3. How serious is the U1803 code in a 2014 GMC Sierra?

- The U1803 code can affect the performance and efficiency of the hybrid/EV powertrain system in the vehicle, so it is important to address this issue promptly.

4. What are some possible repair tips for resolving the U1803 code in a 2014 GMC Sierra?

- Check for loose or damaged wiring connections related to the hybrid/EV powertrain control module 2. Perform a diagnostic scan to reset the code and monitor for recurrence.

5. Can the U1803 code be fixed without professional help in a 2014 GMC Sierra?

- While basic checks like inspecting wiring connections can be done by DIY enthusiasts, resolving communication issues with the hybrid/EV powertrain control module 2 may require professional diagnostics and repair.

6. Is it safe to continue driving with the U1803 code present in a 2014 GMC Sierra?

- It is not recommended to ignore the U1803 code, as it could indicate underlying issues with the hybrid/EV powertrain system that may affect the vehicle's performance and safety.

7. How can a mechanic diagnose the U1803 code in a 2014 GMC Sierra?

- A mechanic can use a scan tool to read the trouble code, inspect the wiring harness and connectors, perform a communication test with the hybrid/EV powertrain control module 2, and check for any related software updates.

8. Are there any recalls or technical service bulletins related to the U1803 code in a 2014 GMC Sierra?

- It's advisable to check with the manufacturer or a certified GMC dealership to see if there are any recalls or technical service bulletins addressing the U1803 code specifically for the 2014 GMC Sierra.

9. How much does it typically cost to repair the U1803 code in a 2014 GMC Sierra?

- The cost of repairing the U1803 code can vary depending on the root cause of the communication issue. It is recommended to get a diagnosis from a professional to determine the exact cost.

10. Can the U1803 code reoccur after it has been repaired in a 2014 GMC Sierra?

- If the root cause of the communication issue with the hybrid/EV powertrain control module 2 is not properly addressed during the repair, the U1803 code may reoccur. Regular maintenance and monitoring can help prevent this.