Chrysler PT Cruiser 2001 Service Manual Supplement page 2762

GENERAL INFORMATION
ature Sensor circuit fails to operate properly the
TCM will use the calculated oil temperature routine
found in prior module year TCM's. If this occurs for
three consecutive key starts, the code will be set.
The TCM will then test the Transmission Temper-
ature Sensor circuit after every 35 OBDII warm-up
starts. If the Transmission Temperatures Sensor
circuit is OK, the Transmission Temperature Sen-
sor data is used in place of the Calculated Oil
Temperature data.
Transmission Effects: If the Transmission Tem-
perature Sensor indicates a temperature below 0°F
or above 240°F at start up, the TCM compares the
calculated oil temperature to the indicated Trans-
mission Temperature Sensor oil temperature. If the
calculated oil temperature differs significantly from
the Transmission Temperature Sensor value, the
calculated oil temperature will be used for that key
start.
Possible causes:
> Wiring or Connector problems in the transmis-
sion temperature sensor signal circuit.
> Defective TRS
> Defective TCM
Name of code: P-1738(75) — High Temperature
Operation Activated
When monitored: Whenever the engine is run-
ning.
Set condition: Immediately once the Overheat
Shift Schedule is activated.
Theory of operation: If the transmission oil tem-
perature rises above 240°F, the overheat shift
schedule is activated (see Transmission Operation
as a function of Transmission Oil Temperature
Section 3.3.2) and the fault code is set. The code is
an information fault code only and is being set to
aid the technician in determining root cause of a
customer driveability issue. The code is also in-
tended to alert the technician to determine if a
cooling system malfunction has occurred or if an
additional transmission air to oil cooler should be
added to the vehicle if the customer regularly drives
in a manner that overheats the transmission. Ex-
tended operation above 240°F will reduce the dura-
bility of the transmission and should be avoided.
Correcting the cooling system malfunction or in-
stalling an additional transmission oil cooler will
improve transmission durability especially for cus-
tomers who operate in city/construction stop and go
traffic, tow trailers regularly, drive aggressively in
low gear or drive regularly in mountainous areas.
Transmission Effects: Information only code.
Overheat shift schedule was activated, no limp-in
conditions occurs. 2nd gear partial EMCC above 25
MPH, 3rd gear EMCC from 28-43 MPH, delayed 3-4
upshift at 43 MPH, early 4-3 coastdown at 41 MPH,
EMCC operation under all conditions above 25
MPH except at closed throttle or 1st gear.
Possible causes:
> Transmission Overfilled with Oil
> Engine cooling fan failure
> Engine thermostat stuck closed
> Radiator corroded or packed with dirt
> Transmission Oil Cooler Plugged
> Customer driving pattern requires additional
transmission cooling (See Theory of Operation
for typical driving patterns that cause overheat-
ing)
Name of code: P-1739(76) — Power-Up at Speed
When monitored: When TCM (transmission con-
trol module) initially powers up.
Set condition: If the TCM powers up while in the
''Drive'' position and the vehicle is going above 20
MPH, the code is set.
Theory of operation: If a vehicle loses power to
TCM, the vehicle will go to the 2nd gear mode since
there is no power available to control the transmis-
sion solenoids. However, if power is restored, the
TCM will power up and normal operation will be
restored. This DTC identifies that power to the
TCM was restored, when the gear selector was in a
''Drive'' position while the vehicle was moving at
speeds above 20 MPH. If a person shifts to Neutral
and cycles the ignition key and quickly shifts to
''Drive'' while moving before the TCM comes out of
its START ROUTINE, the fault can be set. There-
fore it is critical that this faulty diagnosis repair
procedure should only be used if the vehicle is
experiencing intermittent 2nd gear operation and
subsequently a return to normal operation during
normal driving.
Transmission Effects: No
Fault code is for information only when trying to
diagnose intermittent 2nd gear operation and sub-
sequently a return to normal operation.
Possible causes:
– No problem is vehicle is started in ''neutral'' at
speeds above 20 MPH and shifted quickly to
''Drive'' before TCM comes out of the START
ROUTINE.
FOR INTERMITTENT 2ND GEAR OP-
ERATION AND THEN A SUBSEQUENT
RETURN TO
WITHOUT CYCLING THE IGNITION
KEY.
– Intermittent Direct Battery connection be-
tween TCM (60-way pin 56) and battery.
– Intermittent Fused Ignition Switch Output
between TCM (60-way pin 11) and ignition
switch.
14
limp-in condition.
NORMAL OPERATION