These instructions apply to the Lexus RX Mk4 (AL20) 2015-2022.
For other models, please choose your vehicle here.
The Lexus RX (Mk4/AL20, 2015–2022) uses an electronic parking brake (EPB): a console switch and a geared electric motor on each rear caliper in place of a handbrake lever. Before you change the rear pads or discs you have to put the EPB into rear brake service (maintenance) mode so the motors release and the system stops fighting you. On the RX this is a tool-led procedure: Lexus’s factory route uses Techstream, and a generic OBD EPB scan tool does the same job. There is no reliable owner button trick, so use the tool.
What service mode is and why you need it
Each rear caliper carries a motor that drives the parking-brake mechanism against the piston. With the EPB live it holds the piston applied, so the caliper cannot be serviced. Service mode runs the motors back and disables the EPB so it will not re-apply while the caliper is open. With it active the dash shows a parking-brake warning and the brake will not engage. Important on the RX: the rear piston is a screw type, so the mode releases the actuator but you still wind the piston back with the correct tool to fit thicker pads.
Entering EPB service mode on the RX Mk4
Park on level ground, chock a front wheel and switch Brake Hold OFF. Use a scan tool:
- Plug a Techstream (or a generic OBD2 tool with a Lexus/Toyota EPB function) into the DLC3 port and set the ignition to ON (engine off).
- Navigate to Chassis → Electric Parking Brake → Maintenance/Utility → Retract (Rear Brake Pad Replacement).
- Select Retract and wait for the calipers to release fully — the parking-brake indicator flashes then settles once the mode is set.
- Switch off and lift the car.
Entering the mode may log DTC C13A7/43 — expected, and cleared with the tool after the job.
Never force the pistons back by hand
The rule that protects your calipers: never wind or force the EPB pistons back while the system is live. The RX uses a screw-type rear piston, so you must first release the actuator with the tool, then wind the piston back (turn while pushing) with a proper wind-back tool. Forcing the screw against a live, applied actuator strips the mechanism or burns out the motor — a new caliper, not a cheap fix. Skipping service mode and just clamping the piston is the single most common way RX owners destroy a caliper. Retract only electronically, then wind the screw.
Exit and bed-in
With the new pads fitted and the wheels back on, use the tool to close service mode and clear any stored EPB code. Then switch the ignition ON, press the brake pedal firmly and apply and release the EPB two or three times with the console switch so the motors re-learn the thicker pads, checking the brake warning clears. Finish with a road bed-in: from about 30 mph (50 km/h) brake firmly but not to a stop, repeat eight to ten times with cooling gaps, then confirm the parking brake holds on a slope.
Frequently Asked Questions
Does every RX Mk4 have the EPB? Yes — the fourth-generation RX (RX350, RX450h, RX350L, RX450hL) uses the console EPB switch with Brake Hold across the range. There is no lever or foot handbrake.
Do the pistons press in or wind back? They wind back. The rear caliper uses a screw-type EPB piston, so after releasing the actuator you turn the piston clockwise while pushing with a wind-back tool. A straight clamp will not seat it and risks damage.
Can I do it without a scan tool? A no-scan-tool sequence is shared for the RX, but it is fiddly and a failed attempt sets a parking-brake malfunction you then need a tool to clear. A cheap OBD2 EPB tool is the safe, repeatable route.
Is the RX450h hybrid different? The EPB is the same. Make sure the car is fully OFF (not in READY) before connecting the tool; the retract-and-relearn steps are identical.
Why is the parking-brake light still on after the job? It clears once the EPB re-tensions through a full apply-and-release on the new pads and the code is cleared with the tool. If it stays lit, scan for a stored EPB code.
If a warning lamp or stored fault code appears during the job, you can look up what it means on our sister site autodtcs.com.
Independent guide — not affiliated with Lexus. Always follow your official service manual and safety precautions. Read our full disclaimer.