OPERATION
TP-6901 6/14 Operation 15
Throttle Body
Figure4-7
The throttle body controls the operating speed of the
engine according to input from the ECM. Defaults
programmed into the ECM software, along with throttle
position sensors, allow the ECM to control the overall
operation of the engine in response to changing
speeds and loads.
Engine Control Module (ECM)
Figure4-8
The ECM is a digital controller that oversees the
various operating parameters of the engine. The ECM
receives input data from sensors mounted to the
engine and fuel system, and then outputs various
signals to adjust engine operation.
The ECM also performs diagnostic functions on the
fuel system. If a malfunction occurs, the ECM sends a
fault signal to alert the operator to the problem. A
corresponding Diagnostic Trouble Code (DTC) is
generated and stored in memory within the ECM. A
technician can then use a computerized diagnostic
scan tool to retrieve the stored DTC number(s) and
identify the problem.
K0679
K0382