Chrysler 300M 2002 Service Manual page 2810

Name of code: P1790(36) - Fault Immediately
After Shift
When monitored: After a gear ratio error is
stored.
Set condition: This code is set if the associated
gear ratio code is stored within 1.3 seconds after a
shift.
Theory of operation: This code will only be
stored along with a 50 series code. If this code is
set, it indicates the problem is mechanical in na-
ture. When this code exists, diagnosing the trans-
mission should be based on the associated gear
ratio code and primarily mechanical causes should
be considered.
Transmission Effects: None
Possible causes:
> Mechanical causes as listed under associated
gear ratio code.
Name of code: P1775(37) - Solenoid Switch Valve
Latched in TCC Position
When monitored: During an attempted shift into
1st gear.
Set condition: This code is set if three unsuccess-
ful attempts are made to get into 1st gear in one
given key start.
Theory of operation: The solenoid switch valve
(SSV) controls the direction of the transmission
fluid when the LR/TCC solenoid is energized. The
SSV will be in the downshifted position in 1st gear,
thus directing the fluid to the LR clutch circuit. In
2nd, 3rd, and 4th, it will be in the upshifted
position and directs the fluid into the torque con-
verter clutch (TCC).
When shifting into 1st gear, a special hydraulic
sequence is performed to ensure SSV movement
into the downshifted position. The LR pressure
switch is monitored to confirm SSV movement. If
movement is not confirmed (the LR pressure
switch does not close), 2nd gear is substituted for
1st.
Transmission Effects: Transmission will have no
1st gear (2nd gear will be substituted), and no
EMCC operation and the MIL will illuminate after
5 minutes of substituted operation.
Possible causes:
> PRNDL indicates a valid OD code in the hydrau-
lic reverse position
> Valve body - Solenoid valve stuck in TCC posi-
tion
> High idle speed
> Solenoid malfunction - LR pressure switch will
not close
> LR Pressure Switch Sense circuit shorted to
battery
GENERAL INFORMATION
Name of code: P0740(38) - Torque Converter
Clutch Control Circuit
When monitored: During Electronically Modu-
lated Converter Clutch (EMCC)
Set condition:
(a) The transmission must be in EMCC, with the
input speed greater than 1750 RPM. The TCC/LR
solenoid must achieve it's maximum duty cycle and
still not be able to pull the engine speed within 60
RPM of input speed.
b) If the transmission is in FEMCC and the engine
can slip the TCC by more than 100 RPM (Engine
speed - Input speed) for 10 seconds.
The code will be set if one of these event happens
three times at a throttle angle less than 30 degrees.
Theory of operation: When in 2nd, 3rd, or 4th
gear, the torque converter clutch (TCC) can be
locked when certain conditions are met. The TCC
piston is electronically modulated by increasing
the duty cycle of the LR/TCC solenoid until the
torque converter slip (difference between engine
and turbine speed) is within 60 RPM. Then the
LR/TCC solenoid is fully energized (FEMCC / 100%
duty cycle). Torque converter slip is monitored in
FEMCC to ensure adequate clutch capacity.
Transmission Effects: EMCC will still be avail-
able after code is set. MIL will illuminate after 5
minutes of accumulated slip in FEMCC. The trans-
mission will attempt normal operation (no Limp-
in) even after the MIL is illuminated.
Possible causes:
> Worn pump bushing and/or failed torque con-
verter - both should be replaced during a rebuild
with code P0740(38) present
> Solenoid Pressure Switch assembly.
Name of code: P0750(41) - LR Solenoid Circuit
P0755(42) - 2/4 Solenoid Circuit
P0760(43) - OD Solenoid Circuit
P0765(44) - UD Solenoid Circuit
When monitored: Ignition key is turned from off
position to run position and/or ignition key is
turned from crank position to run position, then
every 10 seconds thereafter, or when a gear ratio or
pressure switch error DTC is detected.
Set condition: All four solenoids are tested for
continuity continuously immediately upon start up
and during vehicle operation. For solenoids that
are currently energized, power is momentarily in-
terrupted, then reenergized. For solenoids that are
not currently energized, the solenoid is momen-
tarily energized, then de-energized. Under both
situations, if an inductive spike is not sensed by the
PCM during the continuity check, it is retested
twice. If it fails the test the third time, the appro-
priate code is set.
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