General - Buell 2008 XB SERIES Electrical Diagnostics Manual

DTC P0506 (34), P0507 (34), P0511 (34)

GENERAL

PART NUMBER
HD-44750 DIGITAL TECHNICIAN
IAC Operation
The ECM controls engine idle speed by moving the Idle Air
Control (IAC) motor to open or close a passage around the
throttle plate. It does this by sending voltage pulses to the
proper motor winding of the IAC motor. This causes the pintle
to move in or out of the IAC motor a given distance for each
pulse received.
To increase idle speed, the ECM retracts the pintle,
allowing more air to flow through the throttle body.
To decrease idle seed, the ECM extends the pintle,
allowing less air to flow through the throttle body.
The IAC motor position is measured in steps. This can only be
done by using a computer based diagnostic package called
DIGITAL TECHNICIAN (Part No. HD-44750).
A high number of steps represents a retracted pintle and
open passage around throttle plate. This correlates with
an increase in the amount of air flowing through the throttle
body.
Five steps represents a fully extend pintle. A five reading
indicates an abnormal condition in which the pintle has
been fully extended and has consequently closed the
passage around the throttle plate
Each time the ignition switch is turned ON, the ECM resets the
IAC motor by sending enough pulses to extend the pintle and
effectively close the throttle body. The fully extended value is
the ECM reference point. A given number of steps are then
calculated by the ECM for use in setting the proper idle speed
and IAC position.
Table 2-44. Code Description
DTC CHECK
ENGINE
LAMP CODE
P0506 34
P0507 34
P0511 34
ed02020
Figure 2-64. IAC Test Lamp (Part No. HD-41199-3)
2-84 2008 Buell XB Diagnostics: Engine Management
TOOL NAME
DESCRIPTION
Idle Air Control (IAC) system
RPM higher than expected
Idle Air Control (IAC) system
RPM lower than expected
Idle Air Control (IAC) circuit
ed01302
Figure 2-65. IAC Motor Connector
ed01301
Figure 2-66. IAC Motor Pintle Air Inlet
2.24