Buell 2003XB9S Service Manual page 316

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CODE TYPES
There are two types of trouble codes: current and historic.
Certain codes are also called functional codes. Historic codes
can be read using the check engine lamp diagnostics.
All trouble codes reside in the memory of the ECM until the
code is cleared by DIGITAL TECHNICIAN (Part No. HD-
44750) or a total of 50 trips has elasped. A trip consists of a
start and run cycle, the run cycle lasting at least 30 seconds.
After the 50 trip retention period, the trouble code is automat-
ically erased from memory providing that no subsequent
faults of the same type are detected in that period.
NOTE
Trouble codes relating to the fuel injectors or the ignition coil
can only be fully diagnosed during actuation. For example, a
problem with the ignition coil will be considered a current fault
even after the problem is corrected, since the ECM will not
know of its resolution until after the coil is activated by vehicle
start sequence. In this manner, there may sometimes be a
false indication of the current trouble code.
Current
Current trouble codes are those which presently disrupt
motorcycle operation. See the appropriate flow charts for
solutions.
Historic
If a particular problem happens to resolve itself, the active
status problem is dropped and it becomes a historic fault
rather current fault.
Historic trouble codes are stored for a length of time to assist
in the diagnosis of intermittent faults. The check engine lamp
will not turn on during normal operation if only historic codes
are present.
It is important to note that historic trouble codes may also be
present whenever the system indicates the existence of a
current fault. See 4.4 CHECKING FOR TROUBLE CODES
multiple trouble codes are found.
Functional
Trouble codes 52 through 56 are considered to be functional
codes. They indicate an internal problem with the ECM (trou-
ble codes 52 through 55) or with the camshaft sensor/timing
(trouble code 56).
RETRIEVING TROUBLE
CODES
The fuel injection system provides two levels of diagnostics.
The most sophisticated mode employs using a computer
based diagnostic package called DIGITAL TECHNICIAN
(Part No. HD-44750).
The other mode requires using the check engine lamp.
See 4.5 CHECK ENGINE LAMP DIAGNOSTICS
more information.
MULTIPLE TROUBLE CODES
The throttle position, cam position and bank angle sensors
are all connected to the same reference line (5v REF). If this
line goes to ground or open, multiple trouble codes (codes 11
and 56) may be set.
Also, the ECM, fuel pump, fuel injectors and ignition coil all
receive +12 volts from the ignition relay. If this line should go
to ground the ignition fuse will open.
Always start with the trouble code having the lowest numeri-
cal value. Refer to Table 4-7.
CHECK ENGINE LAMP BLINKS
In addition to alerting the rider to trouble codes, the check
engine lamp will blink during operation to warn of potentially
damaging engine operating temperatures. If the key is in the
on position and the check engine lamp is blinking, the engine
is at a potentially damaging temperature. While this condition
is in effect, the ECM will reduce engine power to assist in
cooling the engine down to a safe operating temperature. The
check engine lamp will blink until the engine has cooled to a
safe operating temperature. This will not set a trouble code.
if
for
2003 Buell XB9S: Fuel System 4-7