REFERENCE INFORMATION
TRANSMISSION
SYSTEM
DTC 73
Pressure Control Solenoid (PCS) Circuit
Current Error (Force Motor Circuit)
Circuit Description:
The Pressure Control Solenoid (PCS) is a TCM-
controlled device used to regulate transmission line
pressure. The TCM compares TP voltage, engine rpm,
and other inputs to determine the appropriate line
pressure of a given load. The TCM will regulate the
pressure by applying a varying amperage to the PCS.
The applied amperage can vary from 0.1 to 1.1 amp.
The TCM then monitors the amperage at the return
line.
DTC 73 Will Set When:
l The return amperage varies greater than
0.16 amp from the commanded amperage.
l All conditions are met for 1 second.
DTC 74
Transmission Input Speed
Sensor (TISS) Circuit
Circuit Description:
The Transmission Input Speed Sensor (TISS)
consists of a permanent magnet surrounded by a
coil of wire. As the forward clutch housing rotates,
an AC voltage is induced in the circuit. The signal
voltage and frequency vary directly with the
forward clutch rotational speed.
DTC 74 WZL Set When:
l Transmission range is not in park or neutral.
l Engine speed is greater than 300 r-pm.
TM 9-2320-387-24-1
DTC 75
System Voltage Low
Circuit Des&p tiorx
Ignition voltage is supplied to the control module to
indicate the status of the ignition switch Battery
voltage is supplied to the control module to, in part,
maintain memory of learned functions and parameters.
DTC 75 Will Set When:
l The ignition is ON.
l Ignition feed voltage to the control module is
less than the graduated scale of:
- -40°F (-40°C) = 7.3 volts.
- 194°F (-90°C) = 10.3 volts.
- 302°F (-150°C) = 11.7 volts.
l Engine speed is greater than 1,000 r-pm.
l All conditions are met for 4 seconds.
DTC 79
Transmission Fluid Overtemp
Circuit Description:
The Transmission Fluid Temperature (TFT) sensor
is a thermistor that controls the signal voltage to
the TCM. The TCM supplies a &volt reference
signal to the sensor on Circuit 923A. When the
transmission fluid is cold, the sensor resistance is
high and the TCM will sense high signal voltage.
As the transmission fluid temperature warms to
normal transmission operating temperature 212°F
(lOO”C), the sensor resistance becomes less and the
voltage decreases to approximately 1.5 to 2.0 volts.
l Transmission output speed is greater than
200 rpm.
l Transmission input speed less than 50 rpm.
l AI1 conditions are met for 2 seconds.
DTC 79 Will Set When:
l Transmission fluid temperature is greater
than 295°F (146°C).
l All conditions are met for 30 minutes.
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