Code Definition

P1850 — Brake Band Apply Solenoid

System: Powertrain  |  Type: Manufacturer-Specific  |  Make: GM

About P1850

P1850 is a manufacturer-specific powertrain diagnostic trouble code recorded for GM vehicles. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

Scanning & clearing: A generic OBD-II scan tool will usually read and clear powertrain (P) codes. For live data, freeze-frame capture, and bi-directional tests you may need a more capable scan tool that supports the vehicle's ECM protocol.

P1850 is a manufacturer-specific code. The same code string on a different make may have a different meaning. Always confirm the code's definition against the vehicle's service information for the specific make and model under test.

Code Information

This DTC sets when the Transmission Control Module (TCM) detects an electrical malfunction in the Brake Band Apply Solenoid circuit, such as an open, a short to ground, or a short to voltage. The brake band apply solenoid controls the application of a transmission band, which manages gear engagement by holding certain elements stationary. A fault in this circuit can cause harsh shifts, improper gear engagement, slipping during gear changes, or the transmission entering a fail safe mode. The fault typically lies in the solenoid winding, its control wiring, or the TCM driver.

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