Autopilot Not Steering in a Straight Line

• Check for any hydraulic leaks

• Check hydraulic fluid level (helm reservoir)

• While checking the fluid level of the helm, check if the reservoir cap is vented

• Inspect hydraulic lines looking for kinks or tight loops and adjust if found

• Is the pump installed per the installation manual? Always double-check a professional installation 

• The return link connects to the lowest reservoir port on the helm. If not connected to the lowest reservoir, change positions

• Check, remove, inspect and reinstall Shadow Drive to insure fluid is not experiencing a blockage. Insure it is installed per mounting considerations

• Check, inspect, and test the helm according to the manufacturer suggested steps to the helm is not leaking and or malfunctioning

• Inspect the power cable of the ECU

• Check the gauge wire used to extend to power and ground, as well as the gauge of electrical wiring used for an extended length of the run. Check the installation manual for the model of hydraulic autopilot for the size of the gauge wire on all extensions

• The preferred location for power is direct to a battery. If it is not connected directly to a battery, check that the fuse/breaker panel is not overloaded, and extension to the battery has a proper gauge for the length of the run

• Check that the terminals at the battery are secure – especially ground connection

• Never extend the Garmin pump to the ECU cable

• For third-party pumps, check the gauge of wire between the pump and the ECU

• Check all connectors on the ECU and the CCU (Reactor) for corrosion, that they are correctly seated, securely connected, and cable length is undamaged. Replace damaged cable, cables with corrosion, or loose locking collars

See Accessing Dealer Mode on a Garmin Autopilot for steps.

• Enter the Verify Steering option under the Dealer Autopilot Set Up > Steering System Set-Up – does the motor move in the correct direction?

• While verifying steering direction

  • Is the pump making a normal noise?

  • When the rudder/engine reaches hard to stop, the helm should not spin on its own

• Lock to Lock – check for how long or how many turns

• Verify that the steering cylinder and pump size match.  Garmin Product Support can assist with this; have the model number of the steering cylinder when calling for assistance

• Check Diagnostic Log for ‘invalid pump’ message Menu > Set Up > System > System Information> On the software page press and hold the far-right hand key until Diagnostics Mode Displays.  Press the far-right key.  Select System Error Logs – Recent Error Log

From a GHC - Garmin Helm Control:

Select Menu > Setup >  Dealer Autopilot Setup > Autopilot Tuning >  Autotune > Begin.

From a current compatible GPSMAP¹:

Select  Options > Settings > My Vessel > Autopilot Installation Setup > Autopilot Tuning > Autotune > Begin.

The vessel performs various zig-zag motions while the Autotune is in progress. When complete, follow the on-screen instructions. If Autotune was unsuccessful, but the ship had not reached maximum cruising speed, increase speed and repeat the Autotune.

From the GHC Controller - Garmin Helm Control

Select Dealer Autopilot Set Up >  Wizards > Select Sea Trial Wizard > Follow the on-screen instructions

From a current GPSMAP¹ device 

Select Options > Settings > My Vessel > Autopilot Installation Setup > Wizards > Sea Trial Wizard > Select Begin

If the Sea Trial fails, please check the numeric value of both the Magnetic Environment and Spin Quality listed within the Diagnostics Mode. 

WARNING: Do Not Alter or Change ANY settings or values while in Diagnostic Mode. It may damage the operational quality and capabilities of the CCU (Reactor).

¹Legacy GPSMAP units have a different menu structure see owner's manual. Finding the Owner's Manual for a Garmin Device

GHC 20:

1. Select Menu

2. Select Set Up

3. Select System

4. Select System Information > Press and hold the far-right soft key until Diagnostics appears on the screen                                                                                                                                                                                          

5. Press the soft key below the Diagnostics option

6. Select Compass Diagnostics

7. Review and take note of the numeric values associated to both the Magnetic Environment and Spin Quality

8. Select Done and return to the home screen

GHC 50:

1. From the autopilot screen select the Three Dots

2. Select Autopilot Setup

3. Select Diagnostics

On the Compass Diagnostics page there are two values to find:  Magnetic Environment and Spin Quality.

Magnetic Environment- This field provides a numeric value representing the Electro-Magnetic Interference (EMI) around/effecting the CCU (Reactor). This value is read from 0-100, 100 is the optimum value.  100 would indicate the device is not experiencing magnetic interference at the current mounting location. If it is a lesser value the device may still function correctly. However, if the value is lower than 70, move the CCU (Reactor) to a different location or find and move the source of EMI.

There are extension cables available for the CCU if the installer needs to re-position it to a location beyond the reach of the supplied Steering Bus Cables or NMEA 2000 cables. Extension cables are under the Accessory Tab for the specific autopilot installed on the boat.

NOTE: The installer should perform a GHC factory reset, re-accomplish the Dockside Wizard and Sea Trial after moving the CCU (Reactor) or removing the source of EMI. 

Spin Quality-This field provides a numeric value representing the quality of the compass calibration. This value is read from 0-100, 100 is the optimum value. 100 would indicate the compass calibration was accomplished without any problems associated to adverse waves, wind, current or operation of the boat during the compass calibration. If it is a lesser value the device may still function correctly. However, if the value is lower than 70, the compass calibration should be re-accomplished. Prior to re-accomplishing the compass calibration ensure the CCU (Reactor) is correctly positioned inside the boat and there is acceptable levels of EMI. 

NOTE: The CCU (Reactor) should be positioned as close to the vessels pivot point, centerline, and waterline as possible.  (See Installation Manual for detailed instructions).

NOTE: Enter Dealer Mode to re-accomplish the Dockside Wizard and Sea Trial (See the link above to enter Dealer Mode from GHC).