C0387 on GMC
Manufacturer-Specific Chassis Code (commonly transfer case / shift-related on GM)
C0387 on GMC vehicles indicates manufacturer-specific chassis code (commonly transfer case / shift-related on gm). Au7o has documented this code across 1 GMC model — most commonly on Jimmy. C0387 is a manufacturer-specific chassis code that falls in a range largely reserved/non-standardized under SAE, so its exact meaning varies by manufacturer. On many GM vehicles it appears alongside transfer-case encoder/shift codes and is generally associated with an inability to complete a requested shift or a related transfer-case/electronic shift fault. Because the precise definition is not standardized, the code should be confirmed against the specific vehicle's service information. In general it points to a chassis driveline or shift-control concern rather than the engine itself. Typical repair costs on GMC range from $150 to $400, depending on the specific model and root cause.
Common Causes of C0387
- •Transfer case encoder motor or shift fault (GM applications)
- •Damaged or corroded wiring/connectors in the affected circuit
- •Failed shift motor or actuator
- •Control module (e.g., transfer case control module) fault
- •Low system voltage or poor ground
- •Mechanical binding in the shift mechanism
C0387 on GMC by Model
GMC Jimmy(1 issue)
- Transfer Case Encoder Motor Failure (AutoTrac)1998-2001
The NP136 AutoTrac transfer case encoder motor fails, preventing the system from engaging 4WD or switching between 2WD and 4WD modes. The "Service 4WD" message illuminates on the dash.
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View C0387 across all makes →Frequently Asked Questions
What does C0387 mean on GMC?▼
C0387 stands for "Manufacturer-Specific Chassis Code (commonly transfer case / shift-related on GM)." C0387 is a manufacturer-specific chassis code that falls in a range largely reserved/non-standardized under SAE, so its exact meaning varies by manufacturer. On many GM vehicles it appears alongside transfer-case encoder/shift codes and is generally associated with an inability to complete a requested shift or a related transfer-case/electronic shift fault. Because the precise definition is not standardized, the code should be confirmed against the specific vehicle's service information. In general it points to a chassis driveline or shift-control concern rather than the engine itself. On GMC specifically, this code is documented across 1 model.
What causes C0387 on GMC vehicles?▼
Common causes on GMC: Transfer case encoder motor or shift fault (GM applications), Damaged or corroded wiring/connectors in the affected circuit, Failed shift motor or actuator, Control module (e.g., transfer case control module) fault, Low system voltage or poor ground. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix C0387 on a GMC?▼
Repair costs on GMC range from $150 to $400, depending on the specific model and root cause.
Which GMC models have C0387 documented?▼
Au7o has documented C0387 on 1 GMC model: Jimmy.