What it means
Fault on the brake transmission shift interlock (BTSI) circuit — prevents shifting from Park unless brake pedal is depressed.
At a glance
- Usually lights the ABS or stability-control warning light
How it works
The brake transmission shift interlock uses the brake-pedal input and a solenoid to prevent shifting out of Park until the brake is applied. This code sets when the interlock control circuit does not operate as expected, so the vehicle may remain in Park or the release function may not be reliable.
Common causes
Most likely first.
- BTSI solenoid faulty or stuck
- Open or shorted solenoid wiring
- Blown fuse or poor power or ground connection
- Brake pedal switch or interlock input fault
Symptoms
- Unable to shift out of Park
- Brake lamps may not respond normally
How to diagnose it
- Check whether the brake lamps respond when the pedal is pressed and whether the shifter releases from Park, because these observations help distinguish an input fault from an interlock fault.
- Read freeze-frame and live data for the brake-pedal switch input and BTSI command while pressing and releasing the pedal.
- Inspect the interlock solenoid connector, wiring, fuse, and grounds for looseness, corrosion, damage, or a blown fuse.
- Test the brake-pedal switch input and solenoid supply and control circuits against the manufacturer's specification.
- If circuit signals are correct, check whether the BTSI solenoid or shifter mechanism binds, following the manufacturer's service procedure.
Common fixes
- Repair a damaged, loose, or corroded BTSI connector or wire.
- Replace a blown fuse after identifying and correcting the underlying cause.
- Adjust or replace a faulty brake-pedal switch if its input is incorrect.
- Replace a failed interlock solenoid or repair a binding shifter mechanism.
Can I keep driving?
Do not force the shifter or bypass the interlock. If the vehicle cannot be shifted securely or the brake lamps do not work, do not drive it; a faulty brake-pedal input can also affect safe braking signals.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.