Honda Accord 2008 Manual page 2571

07/11/02 09:52:59 61TA0000_230_0127
Navigation System
General Troubleshooting Information
General Operation
Refer to the navigation system manual for the
navigation system operating procedures.
Anti-theft Feature
The navigation system and audio unit have a coded
theft protection circuit. Make sure you have the anti-
theft security code before:
• Disconnecting the battery.
• Disconnecting the navigation unit 8P connector.
• Removing the No. 15 (10 A) fuse from the under-hood
fuse/relay box.
After service, reconnect power to the navigation unit,
and turn the ignition switch to ON (II). Enter the 4-digit
anti-theft security code, then select Done.
If the code cannot be found, use the interactive Network
(iN) to look it up. You can view the serial number in one
of the ECU Info diagnostic screens (see page 23-172).
Alternatively, you can find the serial number on the
underside label which is located on the navigation unit
in the trunk.
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
customer's 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
customer's 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 discrepancies between the
vehicle's actual position and the indicated vehicle's
position (GPS vehicle position).
23-126
The following circumstances may cause vehicle
positioning errors:
• Moving the vehicle with the engine stopped and the
vehicle stopped, such as by ferry or tow truck, or if
the vehicle is spun on a turn table.
• 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
– Very bumpy roads
• Tolerances in the system and map inaccuracies
sometimes limit how precisely the vehicle's 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 or
elevation during the following instances:
• For the first 5 to 10 minutes after reconnecting the
battery (this process can take as long as 45 minutes).
• When the satellite signals are blocked by tall
buildings, mountains, tunnels, large trees, inside
parking structures or large trucks.
• When the GPS antenna is blocked by metallic
window tinting or by an object placed above it in the
vehicle. The GPS antenna requires a clear
unobstructed view of the sky.
• 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 aftermarket accessories
including, but not limited to non-OEM in-dash
entertainment units (radio, CD players/changers,
radar detectors and theft recovery systems) and cell
phones placed near the navigation system.
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