U1818 2016 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 2016 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 2016 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 2016 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 2016 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 2016 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 2016 GMC Sierra code?
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Frequently Asked Questions about U1818 2016 GMC Sierra Code
What does OBDII code U1818 mean on a 2016 GMC Sierra?
Code U1818 indicates a loss of communication between the Engine Control Module (ECM) and the Powertrain Expansion Communication Bus, which is responsible for relaying critical vehicle system data.
What are the common symptoms of code U1818?
Symptoms may include a check engine light, reduced engine performance, erratic transmission behavior, and possible failure of various electronic systems.
What causes code U1818 to appear?
Common causes include damaged or corroded wiring, faulty connectors, a failing ECM, a defective powertrain control module, or issues with the communication bus itself.
Can I drive my 2016 GMC Sierra with code U1818 active?
Driving with this code is not recommended as it may result in reduced performance or unexpected system failures that could compromise safety.
How do I diagnose the U1818 code?
Start by inspecting the wiring and connectors between the ECM and powertrain communication bus. Using a scan tool, check for other related codes and test the communication circuits.
What tools are needed to troubleshoot U1818?
A professional-grade OBDII scan tool, a multimeter for testing wiring continuity, and a wiring diagram specific to the 2016 GMC Sierra are typically required.
Can a software update fix code U1818?
A software update might resolve the issue if the problem is related to outdated ECM firmware, but hardware issues like damaged wiring or connectors must be repaired first.
How much does it cost to fix code U1818?
Repair costs can vary widely depending on the cause, ranging from $50-$100 for minor wiring repairs to $500 or more if the ECM or other modules need replacement.
Is U1818 a common issue on a 2016 GMC Sierra?
While not extremely common, U1818 can occur due to wear and tear, especially in vehicles exposed to harsh environments that can damage wiring and connectors.
Will clearing the code fix the problem?
Clearing the code will temporarily turn off the check engine light, but the issue will likely return if the underlying problem is not resolved.
Discuss the causes and fixes for U1818 2016 GMC Sierra OBDII Code
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