6E1–314
X22SE 2.2L ENGINE DRIVEABILITY AND EMISSION
D
Engine coolant temperature (ECT) sensor.
D
Throttle position (TP) sensor.
D
Vehicle speed (vehicle speed sensor).
D
ECM and ignition system supply voltage.
Ignition Control Module (ICM)
The engine control module (ECM) controls engine ignition
through a solid–state switching unit called the ignition
control module (ICM). The software in the ECM uses
input from several sensors to determine the timing,
duration, and strength of the spark.
014RX042
D
The crankshaft position (CKP) sensor sends the ECM
a 58X signal related to the exact position of the
crankshaft.
0013
D
The camshaft position (CMP) sensor sends a signal
related to the position of the camshaft.
014RX007
Based on these sensor signals, as well as engine load
and engine coolant temperature information, the ECM
controls the switching function of the ICM by sending it a
5V signal. As long as the ICM receives the signal, it allows
battery voltage to the ignition coil. That voltage allows a
magnetic field to build in the coil.
When the ECM requires a spark plug to fire, it shuts off the
5V signal to the ICM grounding it internally. This triggers
the ICM to switch off the battery voltage to the ignition coil,
which causes the field to collapse. The lines of magnetic
force pass through the secondary portion of the coil as
they collapse. As they intersect the coil, they induce high
voltage in the secondary ignition circuit which travels
toward ground through the spark plug.
Ignition Control ECM Output
The ECM provides a zero volt (actually about 100 mV to
200 mV) or a 5–volt output signal to the ignition control
(IC) module. When the ignition control (IC) module
receives the 5–volt signal from the ECM, it provides a
ground path for the B+ supply to the primary side of the
coil and creates a magnetic field in the coil. When the
ECM shuts off the 5–volt signal to the ignition control
module, the ground path for the primary coil is broken.
The magnetic field collapses and induces a high voltage
secondary impulse which fires the spark plug and ignites
the air/fuel mixture.
Engine Control Module (ECM)
The ECM is responsible for maintaining proper spark and
fuel injection timing for all driving conditions. To provide
optimum driveability and emissions, the ECM monitors
the input signals from the following components in order
to calculate spark timing:
D
Engine coolant temperature (ECT) sensor.
D
Intake air temperature (IAT) sensor.
D
Throttle position (TP) sensor.
D
Vehicle speed sensor (VSS).
D
Crankshaft position (CKP) sensor.