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G424F(FE) Service Manual
Chapter 5. Engine Management System (EMS)
148
Drive-By-Wire Signal Flow Process
Figure 22. Drive-By-Wire Signal Flow Process
Figure 22 describes the signal flow process of the
MI-07 DBW section. The foot pedal assembly uses
two potentiometers to detect pedal position.
These two signals, accelerator pedal position 1
(APP1) and accelerator pedal position 2 (APP2) are
sent directly to the SECM.
The SECM uses a series of algorithms to self
calibrate and cross check the signals from the pedal
assembly. A demand position for the throttle will
then be derived and sent to the throttle as a throttle
position sensor demand (TPSd). This signal will be
processed through a PID (Proportional, Integral,
Derivative) controller in the SECM to achieve the
appropriate motor-current response then passed to
the throttle. The throttle moves to the commanded
position and provides a feedback signal from the
throttle position sensors (TPS1 and TPS2) to the
SECM.
Ignition Management
In the normal course of events, with the engine
operating at the correct temperature in defined
conditions, the SECM will use load and engine
speed to derive the correct ignition timing. In
addition to load and speed there are other
circumstances under which the SECM may need to
vary the ignition timing, including low engine coolant
temperature, air temperature, start-up, and idle
speed control.
SECM Electrical Mounting
Recommendations
In order to prevent the possibility of any SECM
malfunctions due to EMI/RFI emissions, the SECM
mounting and harness recommendations listed
below:
• The SECM should be mounted in a location that
minimizes the amount of EMI the module is
exposed to by locating it as far as practical from
all high tension components, such as ignition coils,
distributors, spark plug wires, etc. It is
recommended that the SECM be mounted at least
29.5” (749 mm) away from the distributor and
ignition coil, and at least 20” (508 mm) from the
nearest plug wire.
• All wiring harnesses should be routed to minimize
coupling (both radiated and conducted), and be
securely fastened to minimize movement and
maintain proper clearance between the SECM
and all ignition system components.
• The OEM must ensure that a high-quality ground
connection between the SECM and battery
negative (–) is provided and can be maintained for
the useful life of the vehicle. This may require the
use of star-type washers on all ground lug
connections between the SECM and the battery
and/or special preparation of all mating surfaces
that complete the ground connection in order to
ensure that the connection is sound.
Summary of Contents for G20P-5
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Page 31: ...G424F FE Service Manual Chapter 2 Recommended Maintenance 29 ...
Page 36: ...G424F FE Service Manual Chapter 3 Engine Mechanical System 34 MAIN BEARINGS 0 50 UNDERSIZE ...
Page 86: ...G424F FE Service Manual Chapter 3 Engine Mechanical System 84 ...
Page 232: ...G424F FE Service Manual 230 Chapter 8 Basic Troubleshooting ...
Page 234: ...G424F FE Service Manual 232 Chapter 8 Basic Troubleshooting ...