Drivable short-term, but fix now to avoid damage.
This code indicates an electrical fault in the shift/timing solenoid circuit, often the 3-2 shift solenoid. It's commonly caused by a failed solenoid, damaged wiring or connectors, or low and dirty transmission fluid, and occasionally a faulty control module. Repairs usually involve testing the circuit and replacing the solenoid or repairing wiring, sometimes along with a fluid service.
$150 – $1200
Varies by vehicle and root cause.
For short trips, usually yes, but it's risky to keep doing so. A faulty solenoid circuit can cause unpredictable shifting and limp mode, so get it checked soon and drive gently until it's repaired.
Often it's on the lower end, since replacing a shift solenoid or repairing wiring may run a few hundred dollars. Costs can climb if the fault is internal or requires significant labor to access the solenoid.
It can be. An electrical solenoid fault can cause erratic shifting and put the transmission into limp mode, so it should be diagnosed and repaired without long delays.
P0789 is specifically an electrical circuit fault in the shift/timing solenoid, often the 3-2 solenoid. That usually means the solenoid, its wiring, or connectors, rather than worn internal gears.