C0387 2018 GMC Sierra Code - Unable to Complete Shift
Quick Answer
The Transfer Case Motor, also known as the transfer case range actuator, is a bi-directional, permanent magnet, DC motor. Common causes include Faulty Transfer Case Motor (Transfer Case Two/Four Wheel Drive Actuator), Transfer Case Motor harness is open or shorted, Transfer Case Motor 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
- C0387 2018 GMC Sierra indicates Unable to Complete Shift.
- Common causes
- Common causes include Faulty Transfer Case Motor (Transfer Case Two/Four Wheel Drive Actuator), Transfer Case Motor harness is open or shorted, Transfer Case Motor 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 C0387 2018 GMC Sierra Description
If the shift lever detent shaft were to bind, or there was a mechanical failure, or the transfer case clockwise circuit and the transfer case counterclockwise circuit were shorted together, the shift would not be completed. This will cause the Diagnostic Trouble Code (DTC) to be set in order to protect system components from damage.
What are the Possible Causes of the DTC C0387 2018 GMC Sierra?
- Faulty Transfer Case Motor (Transfer Case Two/Four Wheel Drive Actuator)
- Transfer Case Motor harness is open or shorted
- Transfer Case Motor circuit poor electrical connection
How to Fix the DTC C0387 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 C0387 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 C0387 2018 GMC Sierra Code
1. What does the OBDII code C0387 mean on a 2018 GMC Sierra?
C0387 indicates an issue where the transfer case control module (TCCM) is unable to complete a requested shift in the transfer case.
2. What are the common symptoms of the C0387 code on a GMC Sierra?
Symptoms may include the "Service 4WD" light illuminating, inability to shift between 2WD and 4WD modes, or unusual noises from the transfer case.
3. What causes the C0387 code to appear on a 2018 GMC Sierra?
Common causes include a faulty transfer case motor, damaged wiring or connectors, a malfunctioning TCCM, or mechanical issues within the transfer case.
4. Can I continue driving my GMC Sierra with the C0387 code?
While the vehicle may still be drivable, it’s recommended to address the issue promptly as it could affect 4WD functionality and lead to further damage.
5. How do I diagnose the C0387 code on my 2018 GMC Sierra?
Diagnosis typically involves scanning for additional codes, inspecting the transfer case motor and wiring, and testing the TCCM for proper operation.
6. How much does it cost to repair the C0387 code on a GMC Sierra?
Repair costs vary but may range from $200 to $1,000 depending on whether the issue is electrical (e.g., wiring or motor) or mechanical (e.g., transfer case damage).
7. What should I check first when troubleshooting the C0387 code?
Start by inspecting the transfer case motor, wiring harness, and connectors for visible damage or corrosion.
8. Can a software update fix the C0387 code on a 2018 GMC Sierra?
In some cases, a TCCM software update may resolve the issue if it’s related to a programming error. Consult your dealership for confirmation.
9. Does the C0387 code always mean the transfer case motor is bad?
No, the transfer case motor is a common culprit, but the issue could also stem from faulty wiring, the TCCM, or internal transfer case problems.
10. How can I prevent the C0387 code from recurring?
Regular maintenance of the transfer case, including fluid changes, and periodic inspections of electrical components can help prevent recurrence.
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