Chrysler PT Cruiser 2001 Service Manual Supplement page 2750

GENERAL INFORMATION
The oil temperature is measured with a Trans-
mission Temperature Sensor on the 41TE transmis-
sion. The Transmission Temperature Sensor is an
integral component of the Transmission Range Sen-
sor (TRS). If the Transmission Temperature Sensor
is faulty, (DTC P-1799(74)) the transmission will
default to a ''calculated'' oil temperature. Oil tem-
perature will then be calculated through a complex
heat transfer equation which uses engine coolant
temperature, battery/ambient temperature, and en-
gine off time from the Body Control Module (BCM).
These inputs are received from the PCI bus period-
ically and used to initialize the oil temperature at
start up. Once the engine is started, the TCM
updates the transmission oil temperature based on
torque converter slip speed, at vehicle speed, gear,
and engine coolant temperature to determine an
estimated oil temperature during vehicle operation.
Vehicles using ''calculated oil temperature'' track oil
temperature reasonably accurate during normal
operation. However, if a transmission is overfilled, a
transmission oil cooler becomes restricted, or if a
customer drives aggressively in low gear, the calcu-
lated oil temperature will be inaccurate. Conse-
quently the shift schedule selected may be inappro-
priate for the current conditions. The key highlights
of the various shift schedules are as follows:
Extreme Cold: Oil temperature at start up below
-16°F
Goes to ''Cold'' schedule above -12°F oil temper-
ature
Park, Reverse, Neutral and 2nd gear only (pre-
vents shifting which may fail a clutch with fre-
quent shifts)
Cold: Oil temperature at start up above -12°F and
below 36°F
Goes to ''Warm'' schedule above 40°F oil temper-
ature
Delayed 2-3 upshift (approximately 22 -31 MPH)
Delayed 3-4 upshift (45-53 MPH)
Early 4-3 coastdown shift (approximately 30
MPH)
Early 3-2 coastdown shift (approximately 17
MPH)
High speed 4-2, 3-2, 2-1 kickdown shifts are
prevented
No EMCC
Warm: Oil temperature at start up above 36°F and
below 80°F
Goes to ''Hot'' schedule above 80°F oil tempera-
ture
Normal operation (upshifts, kickdowns, and
coastdowns)
No EMCC
Hot: Oil temperature at start up above 80°F
Goes to ''Overheat'' schedule above 240°F oil
temperature
Normal operation (upshifts, kickdowns, and
coastdowns)
Full EMCC, No PEMCC except to engage
FEMCC (Except at closed throttle speeds above
70 -83 MPH)
Overheat: Oil temperature at above 240°F or en-
gine coolant temperature above 244°F
Goes to ''Hot'' below 230°F oil temperature or
''Super Overheat'' above 240°F oil temperature
Delayed 2-3 upshift (25-32 MPH)
Delayed 3-4 upshift (41-48 MPH)
3rd gear FEMCC from 30-48 MPH
3rd gear PEMCC from 27-31 MPH
Super Overheat: Oil temperature above 260°F
Goes to ''Overheat'' below 240°F oil temperature
All ''Overheat'' shift schedules features apply
2nd gear PEMCC above 22 MPH
Above 22 MPH the torque converter will not
unlock unless the throttle is closed (i.e. at 50
MPH a 4th FEMCC to 3rd FEMCC shift will be
made during a part throttle kickdown or a 4th
FEMCC to 2nd PEMCC shift will be made at
wide open throttle) or if a wide open throttle 2nd
PEMCC to 1 kickdown is made.
Causes for operation in the wrong tempera-
ture shift schedule:
Extreme Cold or Cold shift schedule at start up:
Defective Transmission Temperature Sensor circuit.
Overheat or Super Overheat shift schedule after
extended operation:
Operation in city traffic or stop and go traffic
Engine idle speed too high
Aggressive driving in low gear
Trailer towing in OD gear position (use ''3'' posi-
rd
tion (or A/S 3 ) if frequent shifting occurs)
Cooling system failure causing engine to operate
over 230°F
Engine coolant temperature stays too long - If
engine coolant temperature drops below 150°F,
the transmission will disengage EMCC. Ex-
tended operation with the EMCC disengaged will
cause the transmission to overheat.
A defective brake switch will cause the EMCC to
disengage. Extended operation with the EMCC
disengaged will cause the transmission to over-
heat.
Transmission fluid overfilled
Transmission cooler or cooler lines restricted
Defective Transmission Temperature Sensor circuit.
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