Put the Electronic Parking Brake into Service Mode

Last updated: June 12, 2026

The Hyundai Tucson (Mk4/NX4, 2020–Present) carries an electronic parking brake on every trim, so a rear pad change always starts the same way: the rear caliper motors must be wound back into service (maintenance) mode before you touch a piston. Compress a piston the actuator is still holding and you will damage the EPB gearset — on the NX4 that is a caliper-and-motor assembly, not a cheap fix.

What service mode does and why you need it

Each rear caliper on the NX4 has an integrated motor-on-caliper (MOC) actuator that screws the piston out to clamp the disc. At rest the spindle still bears on the piston, leaving no clearance to push it back. Service mode runs both rear motors fully open, retracts the pistons and suspends the auto-apply and Auto Hold functions so nothing re-clamps while you work.

Set expectations on tooling: the NX4 owner’s manual covers only normal apply (pull the switch up) and release (press it down with the brake pressed) — it lists no owner sequence for service mode. Service mode is entered through the OBD-II port with a scan tool that supports the Hyundai EPB function (Autel, iCarsoft CR Pro, Topdon, XTool and similar). There is no verified hold-the-button trick on this generation, so don’t rely on one.

1. Park level, chock the front wheels, leave it in P and switch Auto Hold OFF via the console button so it can’t re-apply.
2. Turn the ignition ON without starting the engine, so the brake module is powered.
3. Connect the scan tool to the OBD-II port below the steering column and open the EPB / chassis-brake menu.
4. Select EPB – Service Mode – Enter. Both rear motors whir back and stop; the EPB warning lamp stays lit while the system is open.
5. Remove the rear wheels, unbolt the caliper and press the pistons straight in — on the MOC caliper they push in, they do not screw in. They should move with normal effort once the motors are retracted.

Critical warning: never force the NX4’s rear pistons back by hand or with a clamp while the EPB is applied. The spindle must be driven back electronically first. Forcing a loaded piston shears the motor gears and can wreck the caliper actuator — an expensive failure that a five-minute service-mode entry avoids.

No tool at all? The documented workaround is to unbolt the actuator motor from the caliper and hand-wind the internal spindle clear with a hex key; avoid simply unplugging the connector, which can latch a fault that needs a dealer reset.

To exit: with the new pads in and the caliper torqued, select Service Mode – Exit on the tool so both motors re-clamp onto the thicker pads (some tools instead prompt an ignition cycle and one EPB apply). Then bed in: press the brake pedal hard several times until firm, click the EPB switch up and down to confirm it grips and releases, switch Auto Hold back on, and drive gently making several moderate 30–40 mph stops before braking hard.

Frequently Asked Questions

Do the NX4 pistons screw in or push in? They push straight in. The motor turns a spindle to apply, but for service you retract that spindle electronically and then the piston compresses with a piston tool or thumb pressure — no winding.

Is there a button-only service mode on the 2020+ Tucson? No. The factory manual gives no owner sequence; service mode is a scan-tool function via the OBD-II port.

Why turn Auto Hold off first? Auto Hold can command the EPB to clamp on its own. Switching it off, plus entering service mode, removes any chance of the system re-applying mid-job.

The EPB warning light is on during the job — should I worry? No, it stays lit while service mode is active. After you exit service mode and apply the brake once it should clear.

Do I have to bleed the brakes? Not for a pad-only change. The hydraulic system stays sealed, so just pump the pedal to restore clearance and bed the pads.

If a brake, ABS or EPB warning lamp lingers afterwards, decode the stored fault before you drive — our sister site autodtcs.com explains what each OBD-II trouble code means.