U1818 2017 GMC Sierra Code - Lost Communication with Engine Control Module on Powertrain Expansion Communication Bus
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 Engine Control Module (ECM), Engine Control Module harness is open or shorted, Engine 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
- U1818 2017 GMC Sierra indicates Lost Communication with Engine Control Module on Powertrain Expansion Communication Bus.
- Common causes
- Common causes include Faulty Engine Control Module (ECM), Engine Control Module harness is open or shorted, Engine 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 U1818 2017 GMC Sierra Description
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 U1818 2017 GMC Sierra?
- Faulty Engine Control Module (ECM)
- Engine Control Module harness is open or shorted
- Engine Control Module circuit poor electrical connection
How to Fix the DTC U1818 2017 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 U1818 2017 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 U1818 2017 GMC Sierra code?
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Frequently Asked Questions about U1818 2017 GMC Sierra Code
1. What does the OBDII code U1818 mean on a 2017 GMC Sierra?
The U1818 code indicates a loss of communication with the Engine Control Module (ECM) on the Powertrain Expansion Communication Bus.
2. What are common symptoms of the U1818 code on a GMC Sierra?
Symptoms may include a check engine light, reduced engine performance, erratic shifting, or failure to start.
3. What causes the U1818 code to appear on a 2017 GMC Sierra?
Common causes include faulty wiring, loose or corroded connectors, a malfunctioning ECM, or issues with the Powertrain Expansion Communication Bus.
4. Can I drive my GMC Sierra with the U1818 code active?
Driving with the U1818 code may lead to reduced performance or potential safety issues. It’s best to address the problem as soon as possible.
5. How do I diagnose the U1818 code on a 2017 GMC Sierra?
Diagnosis typically involves inspecting the wiring and connectors, testing communication bus continuity, and checking the ECM for proper functionality using a scan tool.
6. Is the U1818 code specific to the GMC Sierra?
No, the U1818 code can occur in other GM vehicles, but the specific symptoms and causes may vary.
7. What tools are needed to troubleshoot the U1818 code?
A diagnostic scan tool capable of reading manufacturer-specific codes and a multimeter for testing electrical connections are essential.
8. Can a weak battery cause the U1818 code on a GMC Sierra?
Yes, a weak or failing battery can cause communication issues, including the U1818 code.
9. How much does it cost to fix the U1818 code on a 2017 GMC Sierra?
Repair costs vary depending on the cause, ranging from $50 for simple wiring repairs to over $1,000 if the ECM needs replacement.
10. What should I check first when troubleshooting the U1818 code?
Start by inspecting the wiring and connectors related to the Powertrain Expansion Communication Bus and the ECM for damage or corrosion.
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