diff --git a/libraries/AP_RangeFinder/AP_RangeFinder_MaxsonarI2CXL.cpp b/libraries/AP_RangeFinder/AP_RangeFinder_MaxsonarI2CXL.cpp
index f1582ba794..19e5accf3d 100644
--- a/libraries/AP_RangeFinder/AP_RangeFinder_MaxsonarI2CXL.cpp
+++ b/libraries/AP_RangeFinder/AP_RangeFinder_MaxsonarI2CXL.cpp
@@ -66,7 +66,7 @@ bool AP_RangeFinder_MaxsonarI2CXL::take_reading()
 }
 
 // read - return last value measured by sensor
-int AP_RangeFinder_MaxsonarI2CXL::read()
+int16_t AP_RangeFinder_MaxsonarI2CXL::read()
 {
     uint8_t buff[2];
     int16_t ret_value = 0;
diff --git a/libraries/AP_RangeFinder/AP_RangeFinder_MaxsonarI2CXL.h b/libraries/AP_RangeFinder/AP_RangeFinder_MaxsonarI2CXL.h
index c1024f7f5a..e6e7d22182 100644
--- a/libraries/AP_RangeFinder/AP_RangeFinder_MaxsonarI2CXL.h
+++ b/libraries/AP_RangeFinder/AP_RangeFinder_MaxsonarI2CXL.h
@@ -29,7 +29,7 @@ public:
     bool            take_reading();
 
     // read value from sensor and return distance in cm
-    int             read();
+    int16_t         read();
 
     // heath
     bool            healthy;