B1390 2018 GMC Sierra Code - Control Module Supply Circuit 1
Quick Answer
The vehicle control modules or sensors monitor the system voltage to verify the system voltage is within the normal operating range. Common causes include Low battery voltage, Faulty Control Module, Control Module harness is open or shorted. 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
- B1390 2018 GMC Sierra indicates Control Module Supply Circuit 1.
- Common causes
- Common causes include Low battery voltage, Faulty Control Module, Control Module harness is open or shorted.
- 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 B1390 2018 GMC Sierra Description
What are the Possible Causes of the DTC B1390 2018 GMC Sierra?
- Low battery voltage
- Faulty Control Module
- Control Module harness is open or shorted
- Control Module circuit poor electrical connection
How to Fix the DTC B1390 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 B1390 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 B1390 2018 GMC Sierra Code
1. What does the OBDII code B1390 mean on a 2018 GMC Sierra?
The code B1390 indicates an issue with the "Control Module Supply Circuit 1," which refers to a problem with the power supply to a control module in the vehicle.
2. What are the common symptoms of code B1390 on a 2018 GMC Sierra?
Symptoms may include warning lights on the dashboard, malfunctioning electrical components, communication errors between modules, or the vehicle failing to start.
3. What causes the B1390 code to appear on a 2018 GMC Sierra?
Common causes include a blown fuse, faulty wiring, a damaged control module, corroded or loose electrical connections, or a failing power supply relay.
4. How do I diagnose the B1390 code on my GMC Sierra?
Start by inspecting fuses, checking the wiring for damage or corrosion, and testing the control module’s power and ground connections. Use a multimeter and a scan tool to assist with testing.
5. Can I drive my 2018 GMC Sierra with a B1390 code?
It’s not recommended to drive with this code active, as it may lead to further electrical issues or loss of functionality in critical vehicle systems.
6. How do I fix the B1390 code on a 2018 GMC Sierra?
Repairs may include replacing a blown fuse, repairing damaged wiring, cleaning and tightening electrical connections, or replacing a faulty control module or power supply relay.
7. How much does it cost to repair the B1390 code on a 2018 GMC Sierra?
Repair costs can vary widely based on the root cause, ranging from $50 for a simple fuse replacement to $500 or more for module or wiring repairs.
8. Can a weak battery cause the B1390 code on a 2018 GMC Sierra?
Yes, a weak or failing battery can cause insufficient voltage supply to the control module, triggering the B1390 code.
9. Do I need to reprogram the control module after fixing a B1390 code?
In some cases, if the control module is replaced, reprogramming or reinitialization may be required using a GM-specific scan tool.
10. What tools are needed to troubleshoot the B1390 code on a 2018 GMC Sierra?
You’ll typically need a digital multimeter, a scan tool with GM compatibility, and wiring diagrams specific to the 2018 GMC Sierra.
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