SECTION 1 – ENGINE SYSTEMS
Engine Features (cont.)
Electronic Speedometer and Tachometer
The engine control system calibrates vehicle speed. Any new
speed calibration information mus t be programmed with an EST.
The tachometer signal is generated by the ECM by computing
signals for the Camshaft Position (CMP) sensor and Crankshaft
Position (CKP ) sensor.
Engine Crank Inhibit (ECI)
ECI prevents starter engagement when the engine is running or
when the transmission is in gear.
Event Logging System
The event logging system records engine operation above
maximum rpm (over speed), low coolant level, high coolant
temperature, or low oil pressure. The readings for the odometer
and hourmeter are stored in the ECM memory at the time of an
event and can be retrieved using the EST.
Fast Idle Advance
Fast idle advance increases engine idle speed for faster
warm-up to operating te mperature. This occurs when the ECM
monitors Engine Coolant Temperature (ECT) sensor input and
adjusts fuel injector operation accordingly.
Low idle speed is increased proportionally when the ECT is
below 70 °C (158 °F) at 700 rpm to below -10 °C (14 °F) at 875
rpm maximum.
Service Diagnostics
The Ele ctron ic Service Tool (EST) c ommunicates with the
control system through the public CAN network. The EST
allows the user to retrieve and clear fault codes, run special
diagnostics tests, monitor control system sensors and actuators,
update control system software, and adjust special features.
Form No. 1172040R1
Page 20
Printed in the United States of America
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