Put the Electronic Parking Brake into Service Mode

Last updated: June 11, 2026

The Subaru Impreza (Mk5/GK·GT, 2017–Present) was the first car on the Subaru Global Platform and, on EPB-equipped trims, carries an electronic parking brake with a motor-driven spindle in each rear caliper. That spindle screws the piston outward for parking, so a rear pad change is impossible until the spindle is wound fully back. This guide gives the verified, Impreza-specific procedure — including the honest answer on whether a tool is required.

What service mode does and why you need it

Setting the EPB drives each rear piston out via a threaded spindle. Compress that piston in a straight line and you fight the screw and the gear train, which is how the actuator motor fails. Brake Maintenance Mode commands both rear motors to retract the spindle fully and disables the EPB so it cannot re-apply mid-job. On the Mk5 Impreza the Subaru service manual documents the scan-tool function; it also permits mechanical windback, so you have an option if you have no tool.

Enter service mode (scan tool)

1. Chock the front wheels, ignition ON, engine OFF, foot off the brake.
2. Plug a Subaru-capable bidirectional scan tool (SSM or an aftermarket tool with Subaru EPB support) into the OBD-II port.
3. Open the parking-brake module, select Brake Maintenance Mode, choose Enter, and let the rear spindles whir back.

No-scanner alternatives

1. Windback tool: with the caliper unbolted, fit a right-hand windback tool and turn clockwise on both sides until the piston seats.
2. Motor removal: undo the two cap screws, lift the actuator off, turn the splined shaft clockwise to the hard stop, and refit with a new O-ring.

Never force the pistons back by hand

Do not C-clamp the rear pistons straight in, and never press the brake pedal with a caliper open. The Impreza rear piston seats only by turning — clockwise with a windback tool, or electronically/by-spindle with the motor off. Forcing it ruins the EPB actuator. Crack the brake-fluid reservoir cap before seating the pistons so displaced fluid has somewhere to go.

Exit service mode and bed in

Fit the pads, torque the slider bolts, and reverse your method: with the tool select Exit Maintenance Mode and let it self-test; if you wound back manually, refit any removed motor with a fresh O-ring, then start the car and pump the pedal firm. Apply and release the EPB a couple of times to re-tension against the new pads. Bed in with several moderate 30–40 mph stops, let the brakes cool, and confirm the EPB holds on a slope.

Frequently Asked Questions

Do all Mk5 Imprezas have an EPB? No — lower trims and manual-gearbox cars often keep a conventional lever. Look for the “P” switch by the shifter; this guide is for the EPB versions.

Can I do the rear pads without a scan tool? Yes — a right-hand windback tool (turn clockwise both sides) or removing the actuator motor both work and are factory-recognised on this platform.

Will holding the EPB switch enter service mode? No. The switch only applies or releases the brake; it does not retract the spindle for a pad change.

Why is the brake warning light on the whole time? Because service mode disables the EPB. It clears once you exit and the system re-initialises.

Anything to replace when I take the motor off? Yes — a new actuator O-ring each time the motor is removed, to keep moisture out.

If a VDC or parking-brake light stays on afterwards, decode the stored fault first at autodtcs.com so you know whether it is a simple re-init or a real actuator problem.