Pressure Control Solenoid (PCS) Circuit
Current Error (Force Motor Circuit)
The pressure control solenoid 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 pressure control
solenoid. The applied amperage can vary from 0.1 to
1.1 amp. The TCM then monitors the amperage at the
DTC 73 Will Set When:
. The return amperage varies greater than
0.16 amps from the commanded amperage.
. All conditions are met for 1 second.
Transmission Input Speed
Sensor (TISS) Circuit
The TISS sensor 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 Will Set When
s Trans range not in park or neutral.
. Engine speed greater than 300 rpm.
l Trans output speed greater than 200 rpm.
l Trans input speed less than 50 rpm.
. All conditions are met for 2 seconds.
System Voltage Low
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 greater than 1000 rpm.
l All conditions are met for 4 seconds.
Transmission Fluid Overtemp
The Transmission Fluid Temperature (TFT) sensor
is a thermistor that controls the signal voltage to
the TCM. The TCM supplies a 5-volt reference
signal to the sensor on CKT 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
(100°C), the sensor resistance becomes less and the
voltage decreases to approximately 1.5 to 2.0 volts.
DTC 79 Will Set When:
l Trans fluid temp greater than 295°F (146°C).
l All conditions are met for 30 minutes.