Drive with caution — fix soon.
P0755 indicates a malfunction in shift solenoid "B", which the transmission uses to control fluid flow and engage gears. When this solenoid fails or its circuit has a fault, the transmission can shift erratically or stay locked in one gear. This is most often an electrical or solenoid problem rather than full mechanical failure.
$150 – $500
Varies by vehicle and root cause.
Short trips are usually okay, but don't make a habit of it. The transmission may shift roughly or drop into limp mode, so plan to get it checked soon and avoid hauling heavy loads.
Most repairs land between $150 and $500. Fluid service or wiring repairs cost less, while replacing the shift solenoid or servicing the valve body sits at the higher end.
It's a moderate issue. Your car will likely still move, but continued driving with bad shifting can damage the transmission, so it's worth fixing without much delay.
When the control module can't trust the solenoid, it locks the transmission into a safe gear to protect it. Fixing the solenoid or its circuit usually clears the limp mode.