If a Garmin marine device with an attached sonar transducer shows no sonar option or depth readings, it could be impacted by one or more of the the following factors:

  1.  Cavitation, or air bubbles going across the transducer that interfere with sonar readings. This may be caused by boat speed, transducer placement, or water turbulence
  2.  Sonar transmission is disabled
  3.  Transducer connection
  4. Outdated Software

1. Transducer placement is the most important factor to consider when installing any transducer. Regardless of mounting style, a properly installed transducer delivers a vertical beam that aims straight down toward the bottom, resulting in strong echo returns and accurate depth readings.

This intake shown in the photo above will cause turbulence and send air bubbles over the transducer face as vessel speed increases. The transducer will work great when the vessel is drifting, but will not work well at speed.
This is a excellent installation of a B260. There are no hull protrusions in front or alongside the transducer. The transducer is also installed away from the keel so that the beam is not shaded. An installation like this will give clear bottom readings.

2. Transmission Disabled. The most common issue we see is that the transducer is disabled in the sonar settings. A short video is linked below that demonstrates stopping transducer transmission on a Garmin GPSMAP and then resuming transducer transmission. You can see that the sonar will immediately stop reading when the transmit button is turned off. As soon as the transmit button is hit the sonar starts trasnmitting again and the depth reading changes.

Tech Tip: Many transducers that are left on out of the water and powered on will burn up and stop working. Best practice would be turning off the transducer transmission when you have the boat out of the water (lift or trailer, etc).

3. Transducer Connection. If you are having trouble with a transducer showing "No Sonar Connected" or " Sonar Transducer Disconnected",  you may have an issue with a connection. The best way to tackle this is going down this list of troubleshooting to diagnose. 

  • Check and make sure that all connections going into the MFD are secure and that no pins are bent or missing. 
  • If you have a transducer extension cable being used to extend the transducer, try testing the unit without this extension. We often find that the extension cable will go bad but still put out a sonar reading.
  • If you are connected to a black box module, check all network connections coming from and going to the black box. 
  • If you have access to a Airmar certified installer, ask them to perform a TDT1000 test on the transducer to see if the transducer is testing in range. 

Tech Tip: Garmin marine devices will not display a sonar option on the home screen if it does not detect a connected transducer or sonar module.

4. Outdated Software. If your device is displaying the message "Unsupported Transducer" then you can most likely solve the issue by checking the transducers compatibility with the MFD it's connected to OR by updating the system software. All software updates for GARMIN can be found here. If you have compatibility questions regarding any MFD and transducer, please give our tech line a call, 866-735-5926.