P081F
Brake Transmission Shift Interlock (BTSI) Signal Correlation
The Brake Transmission Shift Interlock prevents shifting out of Park unless the brake pedal is pressed. The TCM compares the brake-pedal input to the BTSI solenoid command and detects an inconsistency — for example shift permitted while brake not pressed, or interlock active while brake is pressed.
- Check engine light: Yes
- Emissions related: No
- Repair difficulty: medium
Symptoms
- Check engine or transmission warning light on
- Harsh, delayed, or missing shifts
- Possible limp mode (locked in one gear)
- Slipping or shuddering during gear changes
Common causes
Ordered by how often each turns out to be the cause.
- Stuck brake pedal switchCommon
- Mis-adjusted BTSI mechanismPossible
Parts involved
- Btsi Solenoid
- Brake Pedal Switch
P081F is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.