U1817 2018 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 2018 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.
Code U1817 2018 GMC Sierra Description
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.
What are the Possible Causes of the DTC U1817 2018 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 2018 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 2018 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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Frequently Asked Questions about U1817 2018 GMC Sierra Code
1. What are common symptoms of OBDII code U1817 in a 2018 GMC Sierra?
- Common symptoms include the check engine light illuminating, issues with the hybrid powertrain system, and potential drivability problems.
2. What does the OBDII code U1817 indicate in a 2018 GMC Sierra?
- The code U1817 indicates a lost communication with the hybrid powertrain control module on the Powertrain Expansion CAN bus malfunction.
3. What are possible causes of the lost communication with the hybrid powertrain control module in a 2018 GMC Sierra?
- Possible causes include faulty wiring or connections, a malfunctioning hybrid powertrain control module, or issues with the Powertrain Expansion CAN bus.
4. How can I diagnose the U1817 code in my 2018 GMC Sierra?
- Diagnosis typically involves using an OBDII scanner to retrieve the code, checking for other related codes, inspecting wiring and connections, and testing the hybrid powertrain control module.
5. Is it safe to continue driving with the U1817 code in a 2018 GMC Sierra?
- It is generally not recommended to continue driving with this code present, as it can lead to potential drivability issues and further damage to the hybrid powertrain system.
6. How can I repair the U1817 code in my 2018 GMC Sierra?
- Repair may involve repairing or replacing damaged wiring, ensuring proper connections, replacing the hybrid powertrain control module if necessary, and addressing any Powertrain Expansion CAN bus issues.
7. Can I reset the U1817 code in my 2018 GMC Sierra by disconnecting the battery?
- While disconnecting the battery may clear the code temporarily, it is important to diagnose and address the underlying issue to prevent the code from reoccurring.
8. How long does it take to repair the U1817 code in a 2018 GMC Sierra?
- The repair time can vary depending on the specific cause of the code, but it may take anywhere from a few hours to a full day to diagnose and repair the issue.
9. Will the U1817 code cause my 2018 GMC Sierra to fail an emissions test?
- Yes, the U1817 code can cause your vehicle to fail an emissions test due to the malfunction in the hybrid powertrain control module.
10. Can a DIY enthusiast fix the U1817 code in a 2018 GMC Sierra?
- While some DIY enthusiasts may be able to diagnose and address simple causes of the code, repairing complex issues related to the hybrid powertrain system may require professional expertise and specialized equipment.
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