User Manual
SENR9977 23
Systems Operation Section
Electronic C ontrol Module (ECM)
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Illustration 26
Electronic control module (ECM)
The ECM functions as the governor and the computer
for the fuel system. The ECM receives all the signals
from the sensors in order to control the timing and
the engine speed.
Reprogramming of the ECM requires factory
passwords. The reasons for having passwords in an
ECM are the following reasons:
•
Prevent unauthorized reprogramming.
•
Prevent unauthorized erasing of logged events.
•
Allow the customer to control certain programmable
engine parameters.
The factory passwords restrict changes to authorized
personnel. Factory passwords are required to
clear any event code. Refer to Troubleshooting,
RENR2696, “Factory Passwords” for more
information on the passwords.
The ECM has an excellent record of reliability. Any
problems in the system are m ost likely to be the
connectors and the wiring harness. The ECM should
be the last item in troubleshooting the engine.
The personality module contains the software with
all the fuel setting information. The information
determines the engine performance. The personality
module is installed behind the access panel on the
ECM.
Flash programming is the method of programming
or updating the
personality module. Refer to
Troubleshooting, RENR2696, “Flash Programming ”
for the instructions on the flash programming of the
personality m
odule.
The ECM is sealed and the ECM needs no routine
adjustment o
r maintenance.
Pressure Sen
sors
g00884730
Illustration 27
Intake manifold pressure sensor
The intake manifold pressure sensor is a three-wire
active sensor that is supplied with power from
the ECM. The sensor provides the ECM with a
measurement of intake manifold pressure in order
to control the air/fuel ratio. This will reduce the
engine smoke during transient conditions. The intake
manifold pressure sensor is also used for engine
monitoring.
The operating range for the intake manifold pressure
sensor ................ 55 kPa to 339 kPa (8 psi to 50 psi)
Required accuracy ......... ±3 % of maximum pressure
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06
Illustration 28
Engine oil pressure sensor
(1) Sens
or com mon
(2) 5 vol
t s upply
(3) Press
ure s ignal