Garmin GPSMAP 498 Owner's Manual

The Garmin GPSMAP 498 is a high-performance marine chartplotter featuring a large color display, preloaded BlueChart g2 coastal charts, built-in GPS receiver, sonar capability (when connected to a compatible transducer), NMEA 0183/2000 connectivity, and rugged waterproof construction. Below are key sections for safety, features, installation, operation, navigation, and troubleshooting.

1. Features at a Glance 2. Installation 3. First-Time Setup 4. Specifications 5. Controls and Settings 6. Connecting Devices 7. Navigation & Chartplotting 8. Sonar Operation 9. Care & Maintenance 10. Regulatory Information 11. Troubleshooting

Features at a Glance

Key components: Large color TFT display, Waterproof housing (IPX7), GPS antenna, SD card slot, Power/data connector, NMEA 0183/2000 ports, Transducer connector.

Feature	Description
Display	High-resolution color TFT, sunlight readable
Charts	Preloaded BlueChart g2 coastal charts with detailed coverage
GPS Receiver	High-sensitivity internal GPS with WAAS/EGNOS support
Sonar	Supports dual-frequency (50/200 kHz) when connected to transducer
Waypoints/Routes	Store up to 3000 waypoints and 50 routes
SD Card Slot	For additional chart data and software updates
NMEA Connectivity	NMEA 0183 and NMEA 2000 compatible for marine networks
Waterproof Rating	IPX7 (submersible to 1 meter for 30 minutes)
Power Input	10-32 V DC marine power system
Mounting	Includes bracket for flush or surface mounting

Installation

Unpack and inspect contents. Select mounting location with clear view of sky.

Mount unit: Use provided bracket; secure to flat surface using stainless steel hardware.
Connect power: Route power cable to 10-32 V DC source; install inline fuse as specified.
Connect transducer: Route cable to transom or through-hull transducer location.
Connect NMEA devices: Wire NMEA 0183 devices to appropriate terminals; connect NMEA 2000 drop cable if used.
Secure all cables with cable ties; ensure waterproof seals are intact.

WARNING! Ensure power is off during installation. Drill holes carefully to avoid damaging vessel structure.

First-Time Setup

Power on unit; follow on-screen prompts.

Acquire GPS signal: Place unit in open sky view; allow several minutes for first fix.
Set language: In SYSTEM menu, select ENGLISH (default).
Set units: Configure nautical/statute miles, feet/fathoms, etc.
Calibrate compass (if applicable): Follow on-screen instructions.
Set chart preferences: Select chart detail level, display orientation (North-up/Head-up).

CAUTION! Ensure mounting surface is strong enough to support unit weight.

Specifications

Display Size: 5-inch diagonal color TFT.
Display Resolution: 480 x 640 pixels.
GPS: High-sensitivity receiver, WAAS/EGNOS capable.
Charts: Preloaded BlueChart g2; accepts BlueChart g2 Vision cards.
Sonar: Dual-frequency (50/200 kHz) capable, depth to 3000 ft.
Waypoints/Routes: 3000 waypoints, 50 routes with up to 250 points each.
Power: 10-32 V DC, 1.5 A max.
Waterproof: IPX7 standard.
Operating Temp: -15°C to 55°C (5°F to 131°F).
Interface: NMEA 0183/2000, SD card slot.

Controls and Settings

Access menus via PAGE and MENU buttons. Front Panel: POWER, PAGE, MENU, ROCKER key (up/down/left/right/ENTER), ZOOM IN/OUT.

On-screen: Chart, Sonar, Highway, Data pages accessible via PAGE button.

Chart Settings: Orientation, Detail, Color Scheme, Depth Shading. Sonar Settings: Frequency, Sensitivity, Range, Noise Rejection. System Settings: Units, Language, Backlight, Alarms, NMEA Setup. Navigation: Waypoint creation, Route planning, Track recording.

Connecting Devices

Power: Red to positive, Black to negative. Transducer: Plug into labeled port. NMEA 0183: Connect to NMEA IN/OUT terminals. NMEA 2000: Use compatible drop cable.

Turn off power before connecting devices.
Match wire colors to terminal labels (NMEA 0183).
Use waterproof connectors for external connections.
Test connections before final cable routing.

Tip: Apply dielectric grease to connectors to prevent corrosion.

Navigation & Chartplotting

Use preloaded BlueChart g2 charts for detailed navigation.

View chart: Press PAGE to select Chart page; use ZOOM to adjust scale.
Create waypoint: Move cursor to location; press ENTER > "Mark Waypoint".
Create route: MENU > Route Planner > Create New; add waypoints in sequence.
Follow route: Select route > "Navigate"; follow course line on chart.
Track recording: Enable in TRACK menu; view track log later.
Man Overboard (MOB): Press and hold PAGE/MOB button to mark current position as MOB.
Data screens: Access Speed, Course, Trip data via PAGE button.

WARNING! Always use charts in conjunction with proper nautical knowledge and visual observation.

Sonar Operation

When connected to compatible transducer, displays depth and bottom contour.

Select Sonar page: Press PAGE until Sonar display appears.
Adjust range: Use ROCKER or menu to set depth range.
Adjust sensitivity: Increase to see weak returns; decrease to reduce clutter.
Change frequency: Select 50 kHz for deeper water, 200 kHz for detail.
Set alarms: Configure shallow/deep water alarms in Sonar menu.

Note: Sonar performance depends on transducer installation and water conditions.

Care & Maintenance

Disconnect power before cleaning. Use fresh water and mild soap; rinse thoroughly. Dry with soft cloth.

CAUTION! Do not use harsh chemicals, abrasives, or high-pressure spray. Store in dry place when not in use.

Regulatory Information

FCC Compliance: This device complies with Part 15 of FCC rules. Operation subject to conditions: (1) device may not cause harmful interference, (2) device must accept any interference received. Contains GPS technology subject to U.S. export laws. Copyright © Garmin Ltd. or its subsidiaries. BlueChart and GPSMAP are trademarks of Garmin Ltd. For support, visit www.garmin.com/support or contact Garmin Product Support.

Troubleshooting

Symptom	Possible Cause	Corrective Action
No power	Power connection/fuse	Check voltage at terminals; verify inline fuse is intact; ensure proper polarity.
No GPS signal	Antenna obstruction	Move to open sky view; ensure no metal obstructions above unit.
Chart not displaying	SD card/chart region	Ensure chart card is fully inserted; verify chart coverage for current area.
No sonar reading	Transducer connection	Check transducer cable connection; ensure transducer is submerged and aimed correctly.
NMEA data not received	Wiring/baud rate	Verify NMEA wiring; check baud rate matches connected device (default 4800).
Display dim	Backlight setting	Adjust backlight in System menu; check power voltage.

Reset: Hold PAGE + POWER during startup for master reset (erases user data).

Service: Contact Garmin Product Support or authorized service center.