diff --git a/libraries/AP_RangeFinder/AP_RangeFinder_PX4_PWM.cpp b/libraries/AP_RangeFinder/AP_RangeFinder_PX4_PWM.cpp
deleted file mode 100644
index 89c2110f74..0000000000
--- a/libraries/AP_RangeFinder/AP_RangeFinder_PX4_PWM.cpp
+++ /dev/null
@@ -1,199 +0,0 @@
-/*
-   This program is free software: you can redistribute it and/or modify
-   it under the terms of the GNU General Public License as published by
-   the Free Software Foundation, either version 3 of the License, or
-   (at your option) any later version.
-
-   This program is distributed in the hope that it will be useful,
-   but WITHOUT ANY WARRANTY; without even the implied warranty of
-   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-   GNU General Public License for more details.
-
-   You should have received a copy of the GNU General Public License
-   along with this program.  If not, see <http://www.gnu.org/licenses/>.
- */
-
-#include <AP_HAL/AP_HAL.h>
-
-#if CONFIG_HAL_BOARD == HAL_BOARD_PX4
-#include <AP_BoardConfig/AP_BoardConfig.h>
-#include "AP_RangeFinder_PX4_PWM.h"
-
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <fcntl.h>
-#include <unistd.h>
-
-#include <drivers/drv_pwm_input.h>
-#include <drivers/drv_hrt.h>
-#include <drivers/drv_sensor.h>
-#include <uORB/topics/pwm_input.h>
-#include <stdio.h>
-#include <errno.h>
-#include <cmath>
-
-extern const AP_HAL::HAL& hal;
-
-extern "C" {
-    int pwm_input_main(int, char **);
-};
-
-/* 
-   The constructor also initialises the rangefinder. Note that this
-   constructor is not called until detect() returns true, so we
-   already know that we should setup the rangefinder
-*/
-AP_RangeFinder_PX4_PWM::AP_RangeFinder_PX4_PWM(RangeFinder::RangeFinder_State &_state, AP_Int16 &powersave_range, float &_estimated_terrain_height) :
-	AP_RangeFinder_Backend(_state),
-    _powersave_range(powersave_range),
-    estimated_terrain_height(_estimated_terrain_height)
-{
-    _fd = open(PWMIN0_DEVICE_PATH, O_RDONLY);
-    if (_fd == -1) {
-        hal.console->printf("Unable to open PX4 PWM rangefinder\n");
-        set_status(RangeFinder::RangeFinder_NotConnected);
-        return;
-    }
-
-    // keep a queue of 20 samples
-    if (ioctl(_fd, SENSORIOCSQUEUEDEPTH, 20) != 0) {
-        hal.console->printf("Failed to setup range finder queue\n");
-        set_status(RangeFinder::RangeFinder_NotConnected);
-        return;
-    }
-
-    // initialise to connected but no data
-    set_status(RangeFinder::RangeFinder_NoData);
-}
-
-/* 
-   close the file descriptor
-*/
-AP_RangeFinder_PX4_PWM::~AP_RangeFinder_PX4_PWM()
-{
-    if (_fd != -1) {
-        close(_fd);
-    }
-    set_status(RangeFinder::RangeFinder_NotConnected);
-}
-
-/* 
-   see if the PX4 driver is available
-*/
-bool AP_RangeFinder_PX4_PWM::detect()
-{
-#if !defined(CONFIG_ARCH_BOARD_PX4FMU_V1) && \
-    !defined(CONFIG_ARCH_BOARD_AEROFC_V1)
-    if (AP_BoardConfig::px4_start_driver(pwm_input_main, "pwm_input", "start")) {
-        hal.console->printf("started pwm_input driver\n");
-    }
-#endif
-    int fd = open(PWMIN0_DEVICE_PATH, O_RDONLY);
-    if (fd == -1) {
-        return false;
-    }
-    close(fd);
-    return true;
-}
-
-void AP_RangeFinder_PX4_PWM::update(void)
-{
-    if (_fd == -1) {
-        set_status(RangeFinder::RangeFinder_NotConnected);
-        return;
-    }
-
-    struct pwm_input_s pwm;
-    float sum_cm = 0;
-    uint16_t count = 0;
-    const float scaling = state.scaling;
-    uint32_t now = AP_HAL::millis();
-
-    while (::read(_fd, &pwm, sizeof(pwm)) == sizeof(pwm)) {
-        // report the voltage as the pulse width, so we get the raw
-        // pulse widths in the log
-        state.voltage_mv = pwm.pulse_width;
-
-        state.last_reading_ms = now;
-
-        // setup for scaling in meters per millisecond
-        float _distance_cm = pwm.pulse_width * 0.1f * scaling + state.offset;
-
-        float distance_delta_cm = fabsf(_distance_cm - _last_sample_distance_cm);
-        _last_sample_distance_cm = _distance_cm;
-
-        if (distance_delta_cm > 100) {
-            // varying by more than 1m in a single sample, which means
-            // between 50 and 100m/s vertically - discard
-            _good_sample_count = 0;
-            continue;
-        }
-
-        if (_good_sample_count > 1) {
-            count++;
-            sum_cm += _distance_cm;
-            _last_timestamp = pwm.timestamp;
-        } else {
-            _good_sample_count++;
-        }
-    }
-
-    // if we haven't received a pulse for 1 second then we may need to
-    // reset the timer
-    int8_t stop_pin = state.stop_pin;
-    uint16_t settle_time_ms = (uint16_t)state.settle_time_ms;
-
-    if (stop_pin != -1 && out_of_range()) {
-        // we are above the power saving range. Disable the sensor
-        hal.gpio->pinMode(stop_pin, HAL_GPIO_OUTPUT);
-        hal.gpio->write(stop_pin, false);
-        set_status(RangeFinder::RangeFinder_NoData);
-        state.distance_cm = 0;
-        state.voltage_mv = 0;
-        return;
-    }
-
-    // if we have not taken a reading in the last 0.2s set status to No Data
-    if (AP_HAL::micros64() - _last_timestamp >= 200000) {
-        set_status(RangeFinder::RangeFinder_NoData);
-    }
-
-    /* if we haven't seen any pulses for 0.5s then the sensor is
-       probably dead. Try resetting it. Tests show the sensor takes
-       about 0.2s to boot, so 500ms offers some safety margin
-    */
-    if (now - state.last_reading_ms > 500U && _disable_time_ms == 0) {
-        ioctl(_fd, SENSORIOCRESET, 0);
-        state.last_reading_ms = now;
-
-        // if a stop pin is configured then disable the sensor for the
-        // settle time
-        if (stop_pin != -1) {
-            hal.gpio->pinMode(stop_pin, HAL_GPIO_OUTPUT);
-            hal.gpio->write(stop_pin, false);            
-            _disable_time_ms = now;
-        }
-    }
-
-    /* the user can configure a settle time. This controls how 
-       long the sensor is disabled for using the stop pin when it is
-       reset. This is used both to make sure the sensor is properly
-       reset, and also to allow for power management by running a low
-       duty cycle when it has no signal 
-    */
-    if (stop_pin != -1 && _disable_time_ms != 0 && 
-        (now - _disable_time_ms > settle_time_ms)) {
-        hal.gpio->write(stop_pin, true);        
-        _disable_time_ms = 0;
-        state.last_reading_ms = now;
-    }
-
-    if (count != 0) {
-        state.distance_cm = sum_cm / count;
-
-        // update range_valid state based on distance measured
-        update_status();
-    }
-}
-
-#endif // CONFIG_HAL_BOARD
diff --git a/libraries/AP_RangeFinder/AP_RangeFinder_PX4_PWM.h b/libraries/AP_RangeFinder/AP_RangeFinder_PX4_PWM.h
deleted file mode 100644
index e8c0c9fde0..0000000000
--- a/libraries/AP_RangeFinder/AP_RangeFinder_PX4_PWM.h
+++ /dev/null
@@ -1,51 +0,0 @@
-/*
-   This program is free software: you can redistribute it and/or modify
-   it under the terms of the GNU General Public License as published by
-   the Free Software Foundation, either version 3 of the License, or
-   (at your option) any later version.
-
-   This program is distributed in the hope that it will be useful,
-   but WITHOUT ANY WARRANTY; without even the implied warranty of
-   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-   GNU General Public License for more details.
-
-   You should have received a copy of the GNU General Public License
-   along with this program.  If not, see <http://www.gnu.org/licenses/>.
- */
-#pragma once
-
-#include "RangeFinder.h"
-#include "RangeFinder_Backend.h"
-
-class AP_RangeFinder_PX4_PWM : public AP_RangeFinder_Backend
-{
-public:
-    // constructor
-    AP_RangeFinder_PX4_PWM(RangeFinder::RangeFinder_State &_state, AP_Int16 &powersave_range, float &_estimated_terrain_height);
-
-    // destructor
-    ~AP_RangeFinder_PX4_PWM(void);
-    
-    // static detection function
-    static bool detect();
-
-    // update state
-    void update(void) override;
-
-protected:
-
-    MAV_DISTANCE_SENSOR _get_mav_distance_sensor_type() const override {
-        return MAV_DISTANCE_SENSOR_UNKNOWN;
-    }
-
-private:
-    int _fd;
-    uint64_t _last_timestamp;
-    uint32_t _disable_time_ms;
-    uint32_t _good_sample_count;
-    float _last_sample_distance_cm;
-
-    AP_Int16 &_powersave_range;
-    float &estimated_terrain_height;
-
-};
diff --git a/libraries/AP_RangeFinder/RangeFinder.cpp b/libraries/AP_RangeFinder/RangeFinder.cpp
index 69de403331..c7734e543d 100644
--- a/libraries/AP_RangeFinder/RangeFinder.cpp
+++ b/libraries/AP_RangeFinder/RangeFinder.cpp
@@ -18,7 +18,6 @@
 #include "AP_RangeFinder_PulsedLightLRF.h"
 #include "AP_RangeFinder_MaxsonarI2CXL.h"
 #include "AP_RangeFinder_MaxsonarSerialLV.h"
-#include "AP_RangeFinder_PX4_PWM.h"
 #include "AP_RangeFinder_BBB_PRU.h"
 #include "AP_RangeFinder_LightWareI2C.h"
 #include "AP_RangeFinder_LightWareSerial.h"
@@ -703,13 +702,7 @@ void RangeFinder::detect_instance(uint8_t instance, uint8_t& serial_instance)
             }
         }
         break;
-#if CONFIG_HAL_BOARD == HAL_BOARD_PX4
-    case RangeFinder_TYPE_PX4_PWM:
-        if (AP_RangeFinder_PX4_PWM::detect()) {
-            drivers[instance] = new AP_RangeFinder_PX4_PWM(state[instance], _powersave_range, estimated_terrain_height);
-        }
-        break;
-#elif CONFIG_HAL_BOARD == HAL_BOARD_CHIBIOS
+#if CONFIG_HAL_BOARD == HAL_BOARD_CHIBIOS
     case RangeFinder_TYPE_PX4_PWM:
         // to ease moving from PX4 to ChibiOS we'll lie a little about
         // the backend driver...