Brake Behaviour when engaging Park in E-pedal mode.

I've noticed that when putting our 2018 LEAF SL in park with E-pedal engaged, the brakes remain locked on all four wheels. This became obvious when doing brake service as all four wheels were locked with brakes applied on the hoist with the car powered off.

I guess you can call this a built in electronic e-brake. The down side of this behaviour occurs during long term storage, particularly after washing the car. The pads/rotors stick as flash rust covers the rotor. I'm not sure that leaving the brake system pressurised (think flex hoses) for a long period of time is so great either. I don't normally use the parking brake when parked level in the garage.

The fix is to either turn off the E-pedal before putting the car into park, or just shift to neutral (with E-Pedal engaged), then power the car off...assuming you are not on a hill!! In this case the parking lock pawl still engages physically in the gearbox, but brake pressure relaxes. If parking on a slope, you should apply the parking brake first, before placing the car into park to avoid leaving pressure on the parking pawl...no point in stressing that component.

Thoughts?

Other than the contact rust concerns, surely it can't maintain brake pressure forever with the brake booster offline? Wouldn't it eventually lose enough pressure to release the brakes?

I would assume that the e-pedal system applies pressure electronically using ABS, so likely the pressure would not release.

From Nissan on e-pedal when the car is stopped:

Stopping:
After the vehicle comes to a complete stop, the hydraulic brake system is automatically activated to keep the car stationary. The system can keep the car stopped on a slope (of up to approximately a 30-percent steepness grade) in uphill and downhill directions.

Evidently if you engage park and turn the car off, the brakes system remains pressurised.

Where would the power come from to hold it, the 12 volt battery after the car is off? If so, it can probably be measured, though it seems like it would be a bad way to run down the 12 volt battery...

No power is likely used to hold pressure...the ABS system has valves to lock/release each wheel.

That said, I have no idea if the ABS system is used to modulate brakes in e-pedal mode...just an educated guess.