Intrepid V6-201 3.3L (1995)
Control Module: Description and Operation
Electronic Transmission Controller Operation
ADAPTIVE CONTROLS
These controls function by reading the input and output speeds over 140 times a second and responding to each new reading.
-
This provides the precise friction element control needed to make smooth clutch-to-clutch shifts for all gear changes.
As with most automatic transaxles, all shifts involve releasing one element and applying a different element.
-
In simplified terms, the upshift logic allows the releasing element to slip backwards slightly, to ensure that it does not have excess capacity; the
apply element is filled until it begins to make the speed change to the higher gear; its apply pressure is then controlled to maintain the desired
rate of speed change until the shift is complete.
The key to providing excellent shift quality is precision;
EXAMPLE As mentioned, the release element for upshifts is allowed to slip backwards slightly; the amount of that slip is typically less than a
total of 20 degrees.
LEARNING
To achieve that precision, the EATX control module learns the characteristics of the particular transaxle that it is controlling.
-
It learns the release rate of the releasing element and the apply time of the applying element.
-
It also learns the rate at which the apply element builds pressure sufficient to begin making the speed change.
-
This method achieves more precision than would be possible with exacting tolerances. It can also adapt to any changes that occur with age or
environment, for example, altitude, temperature, engine output, etc.
KICKDOWN SHIFTING
For kickdown shifts, the control logic allows the releasing element to slip and then controls the rate at which the input (and engine) accelerate;
when the lower gear speed is achieved, the releasing element reapplies to maintain that speed until the apply element is filled.
This provides quick response since the engine begins to accelerate immediately and a smooth torque exchange since the release element can
control the rate of torque increase.
This control can make any power train feel more responsive without increasing harshness.
SUMMARY
Adaptive controls respond to input speed changes They compensate for changes in engine or friction element torque and provide good, consistent
shift quality for the life of the transaxle.
CIRCUIT OPERATION
The transmission control system is used on all automatic transmission applications. It provides smooth and accurate shift points and can adjust as
the transmission wears.
Power for the Transmission Control Module (TCM) is supplied from three sources. One is a direct battery feed on circuit A14. This circuit is
protected by a 20 Amp fuse located in the Power Distribution Center (PDC) cavity B. This circuit is spliced and supplies power for the
transmission control relay.
Power is also supplied, to the TCM, on circuit A41. This is the power supply for the engine starter relay, coil side, and is HOT in the START
position only. Circuit A1, which connects to the ignition switch, supplies power to circuit A41 in the START position and is protected by a 20
Amp fuse located in cavity A of the PDC.
Circuit F11 also supplies power to the TCM and is HOT when the ignition switch is the OFF/RUN/START position. This circuit is protected by a
5 Amp fuse located in the cavity 17 of the junction block. Power for the fuse is supplied on circuit A81. This circuit, A81, is powered by circuit
A1 from the PDC. Circuit A1 is protected by a 20 Amp fuse located in cavity A of the PDC.
Ground for the TCM is supplied on the Z13 circuit, which is a power ground, and circuit Z14, which is a signal ground. Both grounds terminate at
the left front frame rail.
The CCD Data Bus is used to allow the controller to communicate with other controllers and the universal data link connector. The circuits
involved are, D1 for CCD (+), and D2 for CCD (-).
