Navigation System; Symptom Diagnosis - Honda 2004 Odyssey Service Manual

Navigation System

General Troubleshooting Information
General Operation
Refer to the Honda Navigation System manual
for the navigation system operating procedures.
Anti-theft Feature
The navigation system has a coded theft protection
circuit. Be sure to get the customer's 4-digit anti-theft
security code number before;
• Disconnecting the battery.
• Disconnecting the navigation unit 8P connector.
• Removing the NAVIGATION (10A) fuse from the
passenger's under-dash fuse/relay box.
After service, reconnect power to the navigation unit,
and turn the ignition switch ON (II). Enter the 4-digit
anti-theft security code, then select ''Done''.
When replacing the navigation unit, be sure to give the
customer the new anti-theft security code.

Symptom Diagnosis

Certain circumstances and system limitations will result
in occasional vehicle positioning errors. Some
customers may think this indicates a problem with the
navigation system when, in fact, the system is normal.
Keep the following items in mind when interviewing
customers about symptoms of the navigation system.
Self-Inertial Navigation Limitations
The limitations of the self-inertial portion of the
navigation system (the yaw rate sensor and the vehicle
speed signal) can cause some discripancies between
the vehicle's actual position and the indicated vehicle
position (GPS vehicle position). However, if GPS signals
cannot be received, you must tune the vehicle position
manually.
The following circumstances may cause vehicle
positioning errors:
• Moving the vehicle with the navigation system on the
vehicle stopped, such as by ferry or tow truck, or if
the vehicle is spun on a turn table.
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• Tire slippage, changes in tire rolling diameters, and
some driving situations may cause discrepancies in
travel distances. Examples of this include:
– Continuous tire slippage on a slippery surface.
– Driving with snow chains mounted.
– Abnormal tire pressure.
– Incorrect tire size.
– Frequent lane changes across a wide highway.
– Continuous driving on a straight or gently curving
highway.
• Tolerances in the system and map inaccuracies
sometimes limit how precisely the vehicle position is
indicated. Examples of this include:
– Driving on roads not shown on the map (map
matching is not possible).
– Driving on a road that winds in one direction, such
as a loop bridge, an interchange, or a spiral parking
garage.
– Driving on a road with a series of sharp hair-pin
turns.
– Driving near a gradual highway exit or transition.
– Driving on one of two close parallel roads.
– Making many 90 degree turns.
Global Positioning System (GPS) Limitations
The GPS cannot detect the vehicle's position during the
following instances:
• For the first 5 to 10 minutes after reconnecting the
battery.
• When the satellite signals are blocked by tall
buildings, mountains, tunnels, large trees, or large
trucks.
• When the GPS antenna is blocked by something on
the dashboard.
• When there is no satellite signal output (signal output
is sometimes stopped for satellite servicing).
• When the satellite signals are blocked by the
operation of some electronic after-market accessories.
The accuracy of GPS is reduced during these instances:
• When only two satellite signals can be received
(Three satellite signals are required for accurate
positioning).
• When the satellite control centers are experiencing
problems.
• When driving near high tension power lines.