TM 9-2320-280-20-1
TRANSMISSION SYSTEM
(4L80-E)
REFERENCE INFORMATION
DTC 21/22
Throttle Position (TP) Sensor Circuit High/
Throttle Position Sensor Circuit Low
Circuit Description:
The TP sensor contains a resistor strip with one end
connected to a 5-volt supply and the other to ground.
The signal is connected to a movable contact within
the TP sensor. As the accelerator pedal is applied, and
the throttle shaft rotates, the voltage signal will
increase from approximately 0.5 to 4.5 volts.
DTC 21 Will Set When:
l Engine is operating.
l TP sensor signal voltage is greater than 4.9 voits.
c Conditions are met for one second.
DTC 22 Will Set When:
l Engine is operating.
. TP sensor signal voltage is less than 0.2 volt.
l Conditions are met for one second.
DTC 24
Output Speed Sensor Signal
Circuit Decription:
The Output Speed sensor is a magnetic induction type
sensor. Gear teeth pressed onto the output shaft
induce an alternating voltage into the sensor.
DTC 24 Will Set When:
l Not in P/N.
l CKT voltage is constant.
l Engine speed is greater than 3000 rpm.
. Output speed is less than 200 rpm.
l TP is between 10% and 100%.
l All conditions are met for 3 seconds.
DTC 28
Transmission Range (TR) Pressure
Switch Assembly (PSA) Fault
Circuit Description:
The Transmission Range (TR) switch assembly consists
of five normally open pressure switches mounted on
the valve body. The TCM supplies battery voltage to
each range signal. BY grounding one or more of these
circuits through various combinations of the pressure
switches, the TCM assembly detects what transmis-
sion range has been selected by the vehicle operator.
When the transmission electrical connector is discon-
nected, the ground potential for the three range signals
to the TCM will be removed and D2 gear will be indicated
DTC 28 Will Set When:
l Range signals “A” and “C” are both zero volts.
l Condition is met for 2 seconds.
DTC 37/38
Torque Converter Clutch (TCC) Brake
Switch Stuck “ON”/
TCC Brake Switch Stuck “OFF”
Circuit Description:
The normally closed brake switch supplies a B+
signal volt when the TCC brake switch is closed
(brake pedal not applied).
DTC 37 Will Set When:
CKT 810B is open.
- Then vehicle speed is between 5 mph (8 kph)
and 20 mph (32 kph) for greater than 6
seconds.
- Then vehicle speed is greater than 20 mph (32
kph) for greater than 6 seconds.
- For a complete total of seven times.
DTC 38 Will Set When:
TCC brake switch feed CKT 810B has constant
voltage.
- Vehicle speed is greater than 20 mph (32 kph)
for greater than 6 seconds.
.Then vehicle speed is between 5 mph (8 kph)
and 20 mph (32 kph) for greater than 6
seconds.
- For a complete total of seven times.
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