diff --git a/ArduSub/ArduSub.cpp b/ArduSub/ArduSub.cpp
index b11ee21c2b..1263593540 100644
--- a/ArduSub/ArduSub.cpp
+++ b/ArduSub/ArduSub.cpp
@@ -462,6 +462,10 @@ void Sub::three_hz_loop()
 {
 	set_leak_status(water_detector.update());
 
+	failsafe_internal_pressure_check();
+
+	failsafe_internal_temperature_check();
+
     // check if we've lost contact with the ground station
     failsafe_gcs_check();
 
diff --git a/ArduSub/Sub.h b/ArduSub/Sub.h
index 9d7e34d1d3..73520644bb 100644
--- a/ArduSub/Sub.h
+++ b/ArduSub/Sub.h
@@ -303,6 +303,8 @@ private:
         uint8_t ekf                 : 1; // 5   // true if ekf failsafe has occurred
         uint8_t terrain             : 1; // 6   // true if the missing terrain data failsafe has occurred
         uint8_t leak				: 1; // true if leak recently detected
+        uint8_t internal_pressure  : 1;
+        uint8_t internal_temperature :1;
         uint32_t last_leak_warn_ms;      // last time a leak warning was sent to gcs
         uint32_t last_gcs_warn_ms;
 
@@ -1043,6 +1045,8 @@ private:
     void accel_cal_update(void);
 
     void set_leak_status(bool status);
+    void failsafe_internal_pressure_check();
+    void failsafe_internal_temperature_check();
 
     bool surface_init(bool ignore_flags);
     void surface_run();
diff --git a/ArduSub/events.cpp b/ArduSub/events.cpp
index 61d0aaeac7..fca3933306 100644
--- a/ArduSub/events.cpp
+++ b/ArduSub/events.cpp
@@ -1,7 +1,8 @@
 // -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
 
 #include "Sub.h"
-
+#define FS_INTERNAL_PRESSURE_MAX 105000 // 103000 pascal
+#define FS_INTERNAL_TEMPERATURE_MAX 55 // 50 deg C
 /*
  *       This event will be called when the failsafe changes
  *       boolean failsafe reflects the current state
@@ -73,6 +74,48 @@ void Sub::failsafe_battery_event(void)
 
 }
 
+void Sub::failsafe_internal_pressure_check() {
+	uint32_t tnow = AP_HAL::millis();
+	static uint32_t last_pressure_warn_ms;
+	static uint32_t last_pressure_good_ms;
+	if(barometer.get_pressure(0) < FS_INTERNAL_PRESSURE_MAX) {
+		last_pressure_good_ms = tnow;
+		last_pressure_warn_ms = tnow;
+		failsafe.internal_pressure = false;
+		return;
+	}
+
+	if(tnow > last_pressure_good_ms + 2000) {
+		failsafe.internal_pressure = true;
+	}
+
+	if(failsafe.internal_pressure && tnow > last_pressure_warn_ms + 5000) {
+		last_pressure_warn_ms = tnow;
+		gcs_send_text(MAV_SEVERITY_WARNING, "Internal pressure critical!");
+	}
+}
+
+void Sub::failsafe_internal_temperature_check() {
+	uint32_t tnow = AP_HAL::millis();
+	static uint32_t last_temperature_warn_ms;
+	static uint32_t last_temperature_good_ms;
+	if(barometer.get_temperature(0) < FS_INTERNAL_TEMPERATURE_MAX) {
+		last_temperature_good_ms = tnow;
+		last_temperature_warn_ms = tnow;
+		failsafe.internal_temperature = false;
+		return;
+	}
+
+	if(tnow > last_temperature_good_ms + 2000) {
+		failsafe.internal_temperature = true;
+	}
+
+	if(failsafe.internal_temperature && tnow > last_temperature_warn_ms + 5000) {
+		last_temperature_warn_ms = tnow;
+		gcs_send_text(MAV_SEVERITY_WARNING, "Internal temperature critical!");
+	}
+}
+
 void Sub::set_leak_status(bool status) {
 	AP_Notify::flags.leak_detected = status;