AutoCodes – GMC – U1817 2015 GMC Sierra

U1817 2015 GMC Sierra Code - Lost Communication with Hybrid Powertrain Control Module on Powertrain Expansion CAN Bus Malfunction

Quick Answer

Devices connected to the powertrain high-speed General Motor Local Area Network (GMLAN) serial data circuits monitor for serial data communications during normal vehicle operation. Common causes include Faulty Starter/Generator Control Module, Starter/Generator Control Module harness is open or shorted, Starter/Generator Control 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: U1817 2015 GMC Sierra indicates Lost Communication with Hybrid Powertrain Control Module on Powertrain Expansion CAN Bus Malfunction.
Common causes: Common causes include Faulty Starter/Generator Control Module, Starter/Generator Control Module harness is open or shorted, Starter/Generator Control 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 213

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 24, 2023

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code U1817 2015 GMC Sierra Description

Devices connected to the powertrain high-speed General Motor Local Area Network (GMLAN) serial data circuits monitor for serial data communications during normal vehicle operation. Operating information and commands are exchanged among the devices. The devices have prerecorded information about what messages are needed to be exchanged on the serial data circuits, for each virtual network. The messages are supervised and also, some periodic messages are used by the receiver device as an availability indication of the transmitter device. Each message contains the identification number of the transmitter device.
The Motor Control Module and the Hybrid Powertrain Control Module are all internal to the Starter/Generator Control Module. All circuits to the Hybrid Powertrain Control Module are also internal to the Starter/Generator Control Module.
Communication diagnostics for the serial data, including device power and ground as well as the wakeup circuits for the Motor Control Module and the Hybrid Powertrain Control Module are all diagnosed from external sources only to the Starter/Generator Control Module connector because any circuit fault condition within the Starter/Generator Control Module will cause a complete replacement.
The Diagnostic Trouble Code (DTC) will be set when a supervised periodic message that includes the transmitter device availability has not been received.

OBDII Code U1817 2015 GMC Sierra - Lost Communication with Hybrid Powertrain Control Module on Powertrain Expansion CAN Bus Malfunction - AutoCodes.com — U1817 2015 GMC Sierra Code - Lost Communication with Hybrid Powertrain Control Module on Powertrain Expansion CAN Bus Malfunction

What does this mean?

What are the Possible Causes of the DTC U1817 2015 GMC Sierra?

Faulty Starter/Generator Control Module
Starter/Generator Control Module harness is open or shorted
Starter/Generator Control Module circuit poor electrical connection

How to Fix the DTC U1817 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 U1817 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.

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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 U1817 2015 GMC Sierra Code

1. What are the common symptoms of OBDII code U1817 on a 2015 GMC Sierra?

- Common symptoms include loss of communication with the hybrid powertrain control module, issues with the hybrid powertrain system, and potential drivability problems.

2. What does the OBDII code U1817 indicating "Lost Communication with Hybrid Powertrain Control Module on Powertrain Expansion CAN Bus Malfunction" mean?

- This code suggests a communication issue between the vehicle's onboard diagnostic system and the hybrid powertrain control module related to the powertrain expansion CAN bus.

3. What are possible causes of OBDII code U1817 on a 2015 GMC Sierra?

- Common causes may include loose or damaged wiring connections, a faulty hybrid powertrain control module, issues with the powertrain expansion CAN bus, or a problem with the vehicle's computer system.

4. How can I diagnose and repair OBDII code U1817 on my 2015 GMC Sierra?

- To diagnose this code, it is recommended to perform a thorough inspection of the wiring connections, check for any loose connections, and use diagnostic tools to assess the hybrid powertrain control module and powertrain expansion CAN bus. Repair may involve fixing wiring issues, replacing components, or reprogramming the control module.

5. Can I drive my 2015 GMC Sierra with OBDII code U1817 present?

- It is not advisable to continue driving your vehicle with this code present, as it may lead to further damage or safety concerns related to the hybrid powertrain system.

6. How much does it typically cost to repair OBDII code U1817 on a 2015 GMC Sierra?

- The cost of repairing this code can vary depending on the exact cause of the issue, the needed repairs or replacements, and labor costs. It is recommended to consult with a professional mechanic for an accurate estimate.

7. Are there any DIY tips for troubleshooting OBDII code U1817 on a 2015 GMC Sierra?

- DIY troubleshooting tips may include checking for visible wiring issues, ensuring all connections are secure, and using an OBDII scanner to reset the code and monitor for recurrence after any potential fixes.

8. Is OBDII code U1817 a common issue in 2015 GMC Sierra vehicles?

- While not extremely common, issues related to communication with the hybrid powertrain control module and powertrain expansion CAN bus can occur in 2015 GMC Sierra vehicles, leading to the U1817 code.

9. Can a faulty hybrid powertrain control module cause OBDII code U1817 on a 2015 GMC Sierra?

- Yes, a faulty hybrid powertrain control module is one possible cause of OBDII code U1817, as it can disrupt communication with the vehicle's onboard diagnostic system.

10. How urgent is it to address OBDII code U1817 on a 2015 GMC Sierra?

- It is recommended to address OBDII code U1817 promptly to prevent potential drivability issues, further damage to the hybrid powertrain system, or safety concerns while operating the vehicle.